Electrodes Comprising Mixed Active Particles

ABSTRACT

An electrode active material comprising two or more groups of particles having differing chemical compositions, wherein each group of particles comprises a material selected from:
         (a) materials of the formula A 2   e M 2   f O g ; and   (b) materials of the formula A 3   h Mn i O 4 ;
 
wherein
   (i) A 2 , and A 3  are independently selected from the group consisting of Li, Na, K, and mixtures thereof, 0&lt;e≦6 and h≦2.0;   (ii) M 2  is one or more metals, comprising at least one metal selected from the group consisting of Fe, Co, Ni, Mo, V, Zr, Ti, Mo, and Cr, and 1≦f≦6;   (iii) 0&lt;g≦15;   (iv) M 2 , e, f, g, h, and i, are selected so as to maintain electroneutrality of said compound; and   (v) said material of the formula A 3   h Mn i O 4  has an inner and an outer region, wherein the inner region comprises a cubic spinel manganese oxide, and the outer region comprises a manganese oxide that is enriched in Mn +4  relative to the inner region.

This application is a Divisional of application Ser. No. 12/828,472(filed Jul. 1, 2010) which is a continuation of application Ser. No.11/381,602 (filed May 4, 2006, now U.S. Pat. No. 7,771,628) which is acontinuation of U.S. Ser. No. 10/406,890 (filed Apr. 3, 2003, now U.S.Pat. No. 7,041,239).

FIELD OF THE INVENTION

This invention relates to electrode active materials, electrodes, andbatteries. In particular, this invention relates to mixtures or blendsof various active materials that comprise alkali metals, transitionmetals, oxides, phosphates or similar moieties, halogen or hydroxylmoieties, and combinations thereof.

BACKGROUND OF THE INVENTION

A wide variety of electrochemical cells, or “batteries,” are known inthe art. In general, batteries are devices that convert chemical energyinto electrical energy, by means of an electrochemicaloxidation-reduction reaction. Batteries are used in a wide variety ofapplications, particularly as a power source for devices that cannotpracticably be powered by centralized power generation sources (e.g., bycommercial power plants using utility transmission lines).

Batteries can be generally described as comprising three components: ananode that contains a material that is oxidized (yields electrons)during discharge of the battery (i.e., while it is providing power); acathode that contains a material that is reduced (accepts electrons)during discharge of the battery; and an electrolyte that provides fortransfer of ions between the cathode and anode. During discharge, theanode is the negative pole of the battery, and the cathode is thepositive pole. Batteries can be more specifically characterized by thespecific materials that make up each of these three components.Selection of these components can yield batteries having specificvoltage and discharge characteristics that can be optimized forparticular applications.

Batteries can also be generally categorized as being “primary,” wherethe electrochemical reaction is essentially irreversible, so that thebattery becomes unusable once discharged; and “secondary,” where theelectrochemical reaction is, at least in part, reversible so that thebattery can be “recharged” and used more than once. Secondary batteriesare increasingly used in many applications, because of their convenience(particularly in applications where replacing batteries can bedifficult), reduced cost (by reducing the need for replacement), andenvironmental benefits (by reducing the waste from battery disposal).

There are a variety of secondary battery systems known in the art. Amongthe most common systems are lead-acid, nickel-cadmium, nickel-zinc,nickel-iron, silver oxide, nickel metal hydride, rechargeablezinc-manganese dioxide, zinc-bromide, metal-air, and lithium batteries.Systems containing lithium and sodium afford many potential benefits,because these metals are light in weight, while possessing high standardpotentials. For a variety of reasons, lithium batteries are, inparticular, commercially attractive because of their high energydensity, higher cell voltages, and long shelf-life.

Lithium batteries are prepared from one or more lithium electrochemicalcells containing electrochemically active (electroactive) materials.Among such batteries are those having metallic lithium anodes and metalchalcogenide (oxide) cathodes, typically referred to as “lithium metal”batteries. The electrolyte typically comprises a salt of lithiumdissolved in one or more solvents, typically nonaqueous aprotic organicsolvents. Other electrolytes are solid electrolytes (typically polymericmatrixes) that contain an ionic conductive medium (typically a lithiumcontaining salt dissolved in organic solvents) in combination with apolymer that itself may be ionically conductive but electricallyinsulating.

Cells having a metallic lithium anode and metal chalcogenide cathode arecharged in an initial condition. During discharge, lithium metal yieldselectrons to an external electrical circuit at the anode. Positivelycharged ions are created that pass through the electrolyte to theelectrochemically active (electroactive) material of the cathode. Theelectrons from the anode pass through the external circuit, powering thedevice, and return to the cathode.

Another lithium battery uses an “insertion anode” rather than lithiummetal, and is typically referred to as a “lithium ion” battery.Insertion or “intercalation” electrodes contain materials having alattice structure into which an ion can be inserted and subsequentlyextracted. Rather than chemically altering the intercalation material,the ions slightly expand the internal lattice lengths of the compoundwithout extensive bond breakage or atomic reorganization. Insertionanodes contain, for example, lithium metal chalcogenide, lithium metaloxide, or carbon materials such as coke and graphite. These negativeelectrodes are used with lithium-containing insertion cathodes. In theirinitial condition, the cells are not charged, since the anode does notcontain a source of cations. Thus, before use, such cells must becharged in order to transfer cations (lithium) to the anode from thecathode. During discharge the lithium is then transferred from the anodeback to the cathode. During subsequent recharge, the lithium is againtransferred back to the anode where it reinserts. This back-and-forthtransport of lithium ions (Li⁺) between the anode and cathode duringcharge and discharge cycles had led to these cells as being called“rocking chair” batteries.

A variety of materials have been suggested for use as cathode activematerials in lithium ion batteries. Such materials include, for example,MoS₂, MnO₂, TiS₂, NbSe₃, LiCoO₂, LiNiO₂, LiMn₂O₄, V₆O₁₃, V₂O₅, SO₂,CuCl₂. Transition metal oxides, such as those of the general formulaLi_(x)M₂O_(y), are among those materials preferred in such batterieshaving intercalation electrodes. Other materials include lithiumtransition metal phosphates, such as LiFePO₄, and Li₃V₂(PO₄)₃. Suchmaterials having structures similar to olivine or NASICON materials areamong those known in the art. Cathode active materials among those knownin the art are disclosed in S. Hossain, “Rechargeable Lithium Batteries(Ambient Temperature),” Handbook of Batteries, 3d ed., Chapter 34,Mc-Graw Hill (2002); U.S. Pat. No. 4,194,062, Carides, et al., issuedMar. 18, 1980; U.S. Pat. No. 4,464,447, Lazzari, et al., issued Aug. 7,1984; U.S. Pat. No. 5,028,500, Fong et al., issued Jul. 2, 1991; U.S.Pat. No. 5,130,211, Wilkinson, et al., issued Jul. 14, 1992; U.S. Pat.No. 5,418,090, Koksbang et al., issued May 23, 1995; U.S. Pat. No.5,514,490, Chen et al., issued May 7, 1996; U.S. Pat. No. 5,538,814,Kamauchi et al., issued Jul. 23, 1996; U.S. Pat. No. 5,695,893, Arai, etal., issued Dec. 9, 1997; U.S. Pat. No. 5,804,335, Kamauchi, et al.,issued Sep. 8, 1998; U.S. Pat. No. 5,871,866, Barker et al., issued Feb.16, 1999; U.S. Pat. No. 5,910,382, Goodenough, et al., issued Jun. 8,1999; PCT Publication WO/00/31812, Barker, et al., published Jun. 2,2000; PCT Publication WO/00/57505, Barker, published Sep. 28, 2000; U.S.Pat. No. 6,136,472, Barker et al., issued Oct. 24, 2000; U.S. Pat. No.6,153,333, Barker, issued Nov. 28, 2000; PCT Publication WO/01/13443,Barker, published Feb. 22, 2001; and PCT Publication WO/01/54212, Barkeret al., published Jul. 26, 2001; PCT Publication WO/01/84655, Barker etal., published Nov. 8, 2001.

In addition to the above-mentioned materials, mixtures of specificactive materials have been used as cathode active materials in lithiumbatteries. The blending of Li_(x)Mn₂O₄ (also known as spinel) withvarious oxides are among those blends known in the art and are disclosedin U.S. Pat. No. 5,429,890, Pynenburg et al., issued Jul. 4, 1995; andU.S. Pat. No. 5,789,1110, Saidi et al., issued Aug. 4, 1998; bothincorporated herein by reference. U.S. Pat. No. 5,744,265, Barker,issued Apr. 28, 1998 covers the use of physical blends of Li₂CuO₂ withlithium metal chalcogenides. Mixtures of lithium nickel cobalt metaloxide with a lithium manganese metal oxide are disclosed in U.S. Pat.No. 5,783,333, Mayer, issued Jul. 21, 1998; and U.S. Pat. No. 6,007,947,issued Dec. 29, 1999. Further, in a NEC report by Numata et al (NEC Res.Develop. 41, 10, 2000) blended cathodes comprising Li_(x)Mn₂O₄ andLiNi_(0.8)Co_(0.2)O₂ are disclosed.

In general, such a cathode material must exhibit a high free energy ofreaction with lithium, be able to intercalate a large quantity oflithium, maintain its lattice structure upon insertion and extraction oflithium, allow rapid diffusion of lithium, afford good electricalconductivity, not be significantly soluble in the electrolyte system ofthe battery, and be readily and economically produced. However, many ofthe cathode materials known in the art lack one or more of thesecharacteristics. As a result, for example, many such materials are noteconomical to produce, afford insufficient voltage, have insufficientcharge capacity, or lose their ability to be recharged over multiplecycles.

SUMMARY OF THE INVENTION

The present invention provides mixtures or “blends” of electrode activematerials comprising alkali metals, transition metals, and anions suchas oxides, phosphates or similar moieties, halogen or hydroxyl moieties,and combinations thereof. Such electrode active materials comprisegroups of particles having different chemical compositions.

In one embodiment, an active material blend comprises two or more groupsof particles having differing chemical compositions, wherein each groupof particles comprises a material selected from:

-   -   (a) materials of the formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d);    -   (b) materials of the formula A² _(e)M² _(f)O_(g); and    -   (c) materials of the formula A³ _(h)Mn_(i)O₄;        wherein    -   (i) A¹, A², and A³ are independently selected from the group        consisting of Li, Na, K, and mixtures thereof, and 0<a≦8, 0<e≦6;    -   (ii) M¹ is one or more metals, comprising at least one metal        which is capable of undergoing oxidation to a higher valence        state, and 0.8≦b≦3;    -   (iii) M² is one or more metals, comprising at least one metal        selected from the group consisting of Fe, Co, Ni, V, Zr, Ti, Mo        and Cr, and 1≦f≦6;    -   (iv) XY₄ is selected from the group consisting of        X′O_(4-x),Y′_(x), X′O_(4-y)Y′_(2y), X″S₄, and mixtures thereof,        where X′ is selected from the group consisting of P, As, Sb, Si,        Ge, V, S, and mixtures thereof; X″ is selected from the group        consisting of P, As, Sb, Si, Ge, V, and mixtures thereof; Y′ is        halogen; 0≦x<3; and 0<y<2; and 0<c≦3;    -   (v) Z is OH, halogen, or mixtures thereof, and 0≦d≦6;    -   (vi) 0≦g≦15;    -   (vii) M¹, M², X, Y, Z, a, b, c, d, e, f, g, h, i, x and y are        selected so as to maintain electroneutrality of said compound;        and    -   (viii) said material of the formula A³ _(h)Mn_(i)O₄ has an inner        and an outer region, wherein the inner region comprises a cubic        spinel manganese oxide, and the outer region comprises a        manganese oxide that is enriched in Mn⁺⁴ relative to the inner        region.

In a preferred embodiment, M¹ and M² comprise two or more transitionmetals from Groups 4 to 11 of the Periodic Table. In another preferredembodiment, M¹ comprises at least one element from Groups 4 to 11 of thePeriodic Table; and at least one element from Groups 2, 3, and 12-16 ofthe Periodic Table. Preferred embodiments include those where c=1, thosewhere c=2, and those where c=3. Preferred embodiments include thosewhere a≦1 and c=1, those where a=2 and c=1, and those where a≧3 and c=3.Preferred embodiments for compounds having the formula A¹ _(a)M¹_(b)(XY₄)_(c)Z_(d) also include those having a structure similar to themineral olivine (herein “olivines”), and those having a structuresimilar to NASICON(NA Super Ionic CONductor) materials (herein“NASICONs”). In another preferred embodiment, M¹ comprises MO, a+2 ioncontaining a+4 oxidation state transition metal.

In preferred embodiment, M² comprises at least one transition metal fromGroups 4 to 11 of the Periodic Table, and at least one element fromGroups 2, 3, and 12-16 of the Periodic Table. In another preferredembodiment M² is M⁴ _(k)M⁵ _(m)M⁶ _(n), wherein M⁴ is a transition metalselected from the group consisting of Fe, Co, Ni, Cu, V, Zr, Ti, Cr, Moand mixtures thereof; M⁵ is one or more transition metal from Groups 4to 11 of the Periodic Table; M⁶ is at least one metal selected fromGroup 2, 12, 13, or 14 of the Periodic Table; and k+m+n=f. Preferredembodiments of compounds having the formula A² _(e)M² _(f)O_(g) includealkali metal transition metal oxide and more specifically lithium cobaltoxide, lithium nickel oxide, lithium nickel cobalt oxide, lithium nickelcobalt metal oxide and lithium copper oxide. In another preferredembodiment A³ _(h)Mn_(i)O₄ has an inner and an outer region, wherein theinner region comprises a cubic spinel manganese oxide, and the outerregion comprises a manganese oxide that is enriched in Mn⁺⁴ relative tothe inner region.

In another embodiment, active materials comprise two or more groups ofparticles having differing chemical compositions, wherein

-   -   (a) the first group of particles comprises a material of the        formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d) and    -   (b) the second group of particles comprises a material selected        from materials of the formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d);        materials of the formula A² _(e)M³ _(f)O_(g); and mixtures        thereof        wherein    -   (i) A¹ and A² are independently selected from the group        consisting of Li, Na, K, and mixtures thereof, and 0<a≦8, and        0<e≦6;    -   (ii) M¹ and M³ are, independently, one or more metals,        comprising at least one metal which is capable of undergoing        oxidation to a higher valence state, and 0.8≦b≦3, and 1≦f≦6;    -   (iii) XY₄ is selected from the group consisting of        X′O_(4-x)Y′_(x), O_(4-y)Y′_(2y), X″S₄, and mixtures thereof,        where X′ is selected from the group consisting of P, As, Sb, Si,        Ge, V, S, and mixtures thereof; X″ is selected from the group        consisting of P, As, Sb, Si, Ge, V, and mixtures thereof; Y′ is        halogen; 0≦x<3; and 0<y<2; and 0<c≦3;    -   (iv) Z is OH, halogen, or mixtures thereof, and 0≦d≦6;    -   (v) 0<g≦15; and    -   (vi) wherein M¹, M³, X, Y, Z, a, b, c, d, e, f, g, x and y are        selected so as to maintain electroneutrality of said compound.

In a preferred embodiment, M¹ comprises at least one element from Groups4 to 11 of the Periodic Table, and at least one element from Groups 2,3, and 12-16 of the Periodic Table. In another preferred embodiment, M¹comprises MO, a+2 ion containing a+4 oxidation state metal. In anotherpreferred embodiment, M³ is M⁴ _(k)M⁵ _(m)M⁶ _(n), wherein M⁴ is atransition metal selected from the group consisting of Fe, Co, Ni, Cu,V, Zr, Ti, Cr, Mo and mixtures thereof; M⁵ is one or more transitionmetal from Groups 4 to 11 of the Periodic Table; M⁶ is at least onemetal selected from Group 2, 12, 13, or 14 of the Periodic Table. Inanother preferred embodiment A² _(e)M³ _(f)O_(g) comprises a material ofthe formula A³ _(h)Mn_(i)O₄ having an inner and an outer region, whereinthe inner region comprises a cubic spinel manganese oxide, and the outerregion comprises a cubic spinel manganese oxide that is enriched in Mn⁺⁴relative to the inner region. In another preferred embodiment, themixture further comprises a basic compound.

In another embodiment, an active material of this invention comprisestwo or more groups of particles having differing chemical compositions,wherein

-   -   (a) the first group of particles comprises an inner and an outer        region, wherein the inner region comprises a cubic spinel        manganese oxide, and the outer region comprises a manganese        oxide that is enriched in Mn⁺⁴ relative to the inner region; and    -   (b) the second group of particles comprises a material selected        from materials of the formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d);        materials of the formula A² _(e)M³ _(f)O_(g); and mixtures        thereof;        wherein    -   (i) A¹ and A² are independently selected from the group        consisting of Li, Na, K, and mixtures thereof, and 0<a≦8, 0<e≦6;    -   (ii) M¹ and M³ are, independently, one or more metals,        comprising at least one metal which is capable of undergoing        oxidation to a higher valence state, and 0.8≦b≦3, and 1≦f≦6;    -   (iii) XY₄ is selected from the group consisting of        X′O_(4-x)Y′_(x), X′O_(4-y)Y′_(2y), X″S₄, and mixtures thereof,        where X′ is selected from the group consisting of P, As, Sb, Si,        Ge, V, S, and mixtures thereof; X″ is selected from the group        consisting of P, As, Sb, Si, Ge, V, and mixtures thereof; Y′ is        halogen; 0≦x<3; and 0<y<2; and 0<c≦3;    -   (iv) Z is OH, halogen, or mixtures thereof, and 0≦d≦6;    -   (v) 0≦g≦15; and    -   (vi) wherein M¹, M³, X, Y, Z, a, b, c, d, e, f, g, x and y are        selected so as to maintain electroneutrality of said compound.

In another embodiment the active material blend comprises two or moregroups of particles having differing chemical compositions, wherein eachgroup of particles comprises a material selected from:

-   -   (a) materials of the formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d); and    -   (b) materials of the formula LiMn₂O₄ or Li_(1+z)Mn_(2-z)O₄;        wherein    -   (i) A¹ is selected from the group consisting of Li, Na, K, and        mixtures thereof, and 0<a≦8;    -   (ii) M¹ is one or more metals, comprising at least one metal        which is capable of undergoing oxidation to a higher valence        state, and 0.8≦b≦3;    -   (iii) XY₄ is selected from the group consisting of X′        O_(4-x)Y′_(x), X′O_(4-y)Y′_(2y), X″S₄, and mixtures thereof,        where X′ is selected from the group consisting of P, As, Sb, Si,        Ge, V, S, and mixtures thereof; X″ is selected from the group        consisting of P, As, Sb, Si, Ge, V and mixtures thereof; Y′ is        halogen; 0≦x<3; and 0<y<2; and 0<c≦3;    -   (v) Z is OH, halogen, or mixtures thereof, and 0≦d≦6; and    -   (vi) M¹, X, Y, Z, a, b, c, d, x, y and z are selected so as to        maintain electroneutrality of said compound.

Additional particles can be further added to the “binary” mixtures oftwo particles, to form mixtures having three or more particles havingdiffering compositions. The particles can include additional activematerials as well as compounds selected from a group of basic compounds.Such blends can be formed by combining three, four, five, six, etc.compounds together to provide various cathode active material blends.

In particular, in another embodiment, a terniary blend of activematerials includes three groups of particles having differing chemicalcompositions, wherein each group of particles comprises a materialselected from

-   -   (a) materials of the formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d); and    -   (b) materials of the formula A² _(e)M³ _(f)O_(g); and mixtures        thereof; wherein        -   (i) A¹ and A² are independently selected from the group            consisting of Li, Na, K, and mixtures thereof, and 0<a≦8,            and 0<e≦6;        -   (ii) M¹ and M³ independently comprise one or more metals,            comprising at least one metal which is capable of undergoing            oxidation to a higher valence state, and 0.8≦b≦3, and 1≦f≦6;        -   (iii) XY₄ is selected from the group consisting of            X′O_(4-x)Y′_(x), X′O_(4-y)Y′_(2y), X″S₄, and mixtures            thereof, where X′ is selected from the group consisting of            P, As, Sb, Si, Ge, V, S, and mixtures thereof; X″ is            selected from the group consisting of P, As, Sb, Si, Ge, V,            and mixtures thereof; Y′ is halogen; 0≦x<3; and 0<y<2; and            0<c≦3;        -   (iv) Z is OH, halogen, or mixtures thereof, and 0≦d≦6;        -   (v) 0<g≦15; and        -   (vi) wherein M¹, M³, X, Y, Z, a, b, c, d, e, f, g, x and y            are selected so as to maintain electroneutrality of said            compound.

This invention also provides electrodes comprising an electrode activematerial of this invention. Also provided are batteries that comprise afirst electrode having an electrode active material of this invention; asecond electrode having a compatible active material; and anelectrolyte. In a preferred embodiment, the novel electrode material ofthis invention is used as a positive electrode (cathode) activematerial, reversibly cycling lithium ions with a compatible negativeelectrode (anode) active material.

It has been found that the novel electrode materials, electrodes, andbatteries of this invention afford benefits over such materials anddevices among those known in the art. In particular, it has been foundthat mixtures of active materials among those of this inventioncompensate and augment characteristics exhibited by component activematerials during battery cycling. Such characteristics include enhancedcycling capacity, increased capacity retention of the cell, improvedoperating temperature characteristics, and improved voltage profiles.Thus, batteries may be designed having performance characteristics thatare optimized for given desired end-use applications, having reducedcost, improved safety, and reduced environmental concerns associatedwith battery manufacturing and performance. Specific benefits andembodiments of the present invention are apparent from the detaileddescription set forth herein. It should be understood, however, that thedetailed description and specific examples, while indicating embodimentsamong those preferred, are intended for purposes of illustration onlyand are not intended to limited the scope of the invention.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating specific embodiments of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides electrode active materials for use in abattery. The present invention further provides batteries comprisingmixtures of electrode active materials and electrolytes. As used herein,“battery” refers to a device comprising one or more electrochemicalcells for the production of electricity. Each electrochemical cellcomprises an anode, a cathode, and an electrolyte. Two or moreelectrochemical cells may be combined, or “stacked,” so as to create amulti-cell battery having a voltage that is the sum of the voltages ofthe individual cells.

The electrode active materials of this invention may be used in theanode, the cathode, or both. Preferably, the active materials of thisinvention are used in the cathode. As used herein, the terms “cathode”and “anode” refer to the electrodes at which oxidation and reductionoccur, respectively, during battery discharge. During charging of thebattery, the sites of oxidation and reduction are reversed. Also, asused herein, the words “preferred” and “preferably” refer to embodimentsof the invention that afford certain benefits, under certaincircumstances. However, other embodiments may also be preferred, underthe same or other circumstances. Furthermore, the recitation of one ormore preferred embodiments does not imply that other embodiments are notuseful and is not intended to exclude other embodiments from the scopeof the invention.

Electrode Active Materials:

The present invention provides mixtures or blends of electrochemicallyactive materials (herein “electrode active materials”). The term “blend”or “mixture” refers to a combination of two or more individual activematerials in a physical mixture. Preferably, each individual activematerial in a blend retains its individual chemical composition aftermixing under normal operating conditions, except such variation as mayoccur during substantially reversible cycling of the battery in whichthe material is used. Such mixtures comprise discrete regions, or“particles,” each comprising an active material with a given chemicalcomposition, preferably a single active material. Preferably, thematerials of this invention comprise a substantially homogenousdistribution of particles.

The electrode active materials of the present invention comprise activematerials of the general formulas A_(a)M_(b)(XY₄)_(c)Z_(d) andA_(e)M_(f)O_(g).

I. A_(a)M_(b)(XY₄)_(c)Z_(d) Active Materials:

In one embodiment of this invention, active materials include compoundshaving the formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d). Such electrode activematerials of the formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d) include lithium orother alkali metals, a transition metal, a phosphate or similar moiety,and a halogen or hydroxyl moiety. (As used herein, the word “include,”and its variants, is intended to be non-limiting, such that recitationof items in a list is not to the exclusion of other like items that mayalso be useful in the materials, compositions, devices, and methods ofthis invention.)

A¹ is selected from the group consisting of Li (lithium), Na (sodium), K(potassium), and mixtures thereof. In a preferred embodiment, A is Li,or a mixture of Li with Na, a mixture of Li with K, or a mixture of Li,Na and K. In another preferred embodiment, A¹ is Na, or a mixture of Nawith K. Preferably “a” is from about 0.1 to about 8, more preferablyfrom about 0.2 to about 6. Where c=1, a is preferably from about 0.1 toabout 3, preferably from about 0.2 to about 2. In a preferredembodiment, where c=1, a is less than about 1. In another preferredembodiment, where c=1, a is about 2. Where c=2, a is preferably fromabout 0.1 to about 6, preferably from about 1 to about 6. Where c=3, ais preferably from about 0.1 to about 6, preferably from about 2 toabout 6, preferably from about 3 to about 6. In another embodiment, “a”is preferably from about 0.2 to about 1.0.

In a preferred embodiment, removal of alkali metal from the electrodeactive material is accompanied by a change in oxidation state of atleast one of the metals comprising M¹. The amount of said metal that isavailable for oxidation in the electrode active material determines theamount of alkali metal that may be removed. Such concepts are, ingeneral application, well known in the art, e.g., as disclosed in U.S.Pat. No. 4,477,541, Fraioli, issued Oct. 16, 1984; and U.S. Pat. No.6,136,472, Barker, et al., issued Oct. 24, 2000, both of which areincorporated by reference herein.

Referring to the general formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d), theamount (a′) of alkali metal that can be removed, as a function of thequantity (b′) and valency (V^(M) ¹ ) of oxidizable metal, is

a′=b′(ΔV ^(m) ¹ ),

where ΔV^(M) ¹ is the difference between the valence state of the metalin the active material and a valence state readily available for themetal. (The term oxidation state and valence state are used in the artinterchangeably.) For example, for an active material comprising iron(Fe) in the +2 oxidation state, ΔV^(M) ¹ =1, wherein iron may beoxidized to the +3 oxidation state (although iron may also be oxidizedto a +4 oxidation state in some circumstances). If b=2 (two atomic unitsof Fe per atomic unit of material), the maximum amount (a′) of alkalimetal (oxidation state +1) that can be removed during cycling of thebattery is 2 (two atomic units of alkali metal). If the active materialcomprises manganese (Mn) in the +2 oxidation state, ΔV^(M) ¹ =2, whereinmanganese may be oxidized to the +4 oxidation state (although Mn mayalso be oxidized to higher oxidation states in some circumstances).Thus, in this example, the maximum amount (a′) of alkali metal that canbe removed from a formula unit of active material during cycling of thebattery is 4 atomic units, assuming that a≧4.

In general, the value of “a” in the active materials can vary over awide range. In a preferred embodiment, active materials are synthesizedfor use in preparing a lithium ion battery in a discharged state. Suchactive materials are characterized by a relatively high value of “a”,with a correspondingly low oxidation state of M¹ of the active material.As the battery is charged from its initial uncharged state, an amount a′of lithium is removed from the active material as described above. Theresulting structure, containing less lithium (i.e., a−a′) than in theas-prepared state as well as the transition metal in a higher oxidationstate than in the as-prepared state, is characterized by lower values ofa, while essentially maintaining the original value of b. The activematerials of this invention include such materials in their nascentstate (i.e., as manufactured prior to inclusion in an electrode) andmaterials formed during operation of the battery (i.e., by insertion orremoval of Li or other alkali metal).

The value of “b” and the total valence of M¹ in the active material mustbe such that the resulting active material is electrically neutral(i.e., the positive charges of all anionic species in the materialbalance the negative charges of all cationic species), as furtherdiscussed below. The net valence of M¹ (V^(M) ¹ ) having a mixture ofelements (M_(α), M_(β) . . . M_(ω)) may be represented by the formula

V ^(M) ¹ =V ^(M) ^(α) b ₁ +V ^(M) ^(β) b ₂ + . . . V ^(M) ^(ω) b _(ω),

where b₁+b₂+ . . . b_(ω)=1, and V^(M) ^(α) is the oxidation state ofM_(α), V^(M) ^(β) is the oxidation state of M_(β), etc. (The net valenceof M and other components of the electrode active material is discussedfurther, below.)

M¹ is one or more metals including at least one metal that is capable ofundergoing oxidation to a higher valence state (e.g., Co⁺²→Co⁺³),preferably a transition metal selected from Groups 4-11 of the PeriodicTable. As referred to herein, “Group” refers to the Group numbers (i.e.,columns) of the Periodic Table as defined in the current IUPAC PeriodicTable. See, e.g., U.S. Pat. No. 6,136,472, Barker et al., issued Oct.24, 2000, incorporated by reference herein.

Transition metals useful herein include those selected from the groupconsisting of Ti (Titanium), V (Vanadium), Cr (Chromium), Mn(Manganese), Fe (Iron), Co (Cobalt), Ni (Nickel), Cu (Copper), Zr(Zirconium), Nb (Niobium), Mo (Molybdenum), Ru (Ruthenium), Rh(Rhodium), Pd (Palladium), Ag (Silver), Cd (Cadmium), Hf (Hafnium), Ta(Tantalum), W (Tungsten), Re (Rhenium), Os (Osmium), Ir (Iridium), Pt(Platinum), Au (Gold), Hg (Mercury), and mixtures thereof. Preferred arethe first row transition series (the 4th Period of the Periodic Table),selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, andmixtures thereof. Particularly preferred transition metals useful hereinclude Fe, Co, Mn, Cu, V, Ni, Cr, and mixtures thereof. In someembodiments, mixtures of transition metals are preferred. Although, avariety of oxidation states for such transition metals are available, insome embodiments it is preferred that the transition metals have a +2oxidation state.

M¹ may also comprise non-transition metals and metalloids. Among suchelements are those selected from the group consisting of Group 2elements, particularly Be (Beryllium), Mg (Magnesium), Ca (Calcium), Sr(Strontium), Ba (Barium); Group 3 elements, particularly Sc (Scandium),Y (Yttrium), and the lanthanides, particularly La (Lanthanum), Ce(Cerium), Pr (Praseodymium), Nd (Neodymium), Sm (Samarium); Group 12elements, particularly Zn (zinc) and Cd (cadmium); Group 13 elements,particularly B (Boron), Al (Aluminum), Ga (Gallium), In (Indium), Tl(Thallium); Group 14 elements, particularly Si (Silicon), Ge(Germanium), Sn (Tin), and Pb (Lead); Group 15 elements, particularly As(Arsenic), Sb (Antimony), and Bi (Bismuth); Group 16 elements,particularly Te (Tellurium); and mixtures thereof. Preferrednon-transition metals include the Group 2 elements, Group 12 elements,Group 13 elements, and Group 14 elements. Particularly preferrednon-transition metals include those selected from the group consistingof Mg, Ca, Zn, Sr, Pb, Cd, Sn, Ba, Be, Al, and mixtures thereof.Particularly preferred are non-transition metals selected from the groupconsisting of Mg, Ca, Zn, Ba, Al, and mixtures thereof.

In a preferred embodiment, M¹ comprises one or more transition metalsfrom Groups 4 to 11. In another preferred embodiment, M¹ comprises atleast one transition metal from Groups 4 to 11 of the Periodic Table;and at least one element from Groups 2, 3, and 12-16 of the PeriodicTable. Preferably, M¹ comprises a transition metal selected from thegroup consisting of Fe, Co, Ni, Mn, Cu, V, Zr, Ti, Cr, Mo and mixturesthereof. More preferably, M¹ comprises a transition metal selected fromthe group consisting of Fe, Co, Mn, Ti, and mixtures thereof. In apreferred embodiment, M¹ comprises Fe. In another preferred embodiment,M¹ comprises Co or a mixture of Co and Fe. In another preferredembodiment, M¹ comprises Mn or a mixture of Mn and Fe. In anotherpreferred embodiment M¹ comprises a mixture of Fe, Co, and Mn.Preferably, M¹ further comprises a non-transition metal selected fromthe group consisting of Mg, Ca, Zn, Sr, Pb, Cd, Sn, Ba, Be, Al, andmixtures thereof. More preferably, M¹ comprises a non-transition metalselected from the group consisting of Mg, Ca, Al, and mixtures thereof.

In another preferred embodiment, M¹ comprises MO, a +2 ion containing a+4 oxidation state metal. Preferably M is selected from the groupconsisting of V (Vanadium), Ta (Tantalum), Nb (Niobium), and Mo(Molybdenum). Preferably M is V.

As further discussed herein, “b” is selected so as to maintainelectroneutrality of the electrode active material. In a preferredembodiment, where c=1, b is from about 1 to about 2, preferably about 1.In another preferred embodiment, where c=2, b is from about 2 to about3, preferably about 2.

XY₄ is an anion, preferably selected from the group consisting ofX′O_(4-x)Y′_(x), X′O_(4-y)Y′_(2y), X″S₄, and mixtures thereof, where X′is selected from the group consisting of P (phosphorus), As (arsenic),Sb (antimony), Si (silicon), Ge (germanium), V (vanadium), S (sulfur),and mixtures thereof; X″ is selected from the group consisting of P, As,Sb, Si, Ge, V and mixtures thereof. XY₄ anions useful herein includephosphate, silicate, germinate, vanadate, arsenate, antimonite, sulfuranalogs thereof, and mixtures thereof. In a preferred embodiment, X′ andX″ are, respectively, selected from the group consisting of P, Si, andmixtures thereof. In a particularly preferred embodiment, X′ and X″ areP.

Y′ is selected from the group consisting of halogen, S, N, and mixturesthereof. Preferably Y′ is F (fluorine). In a preferred embodiment 0<x<3;and 0<y<2, such that a portion of the oxygen (O) in the XY₄ moiety issubstituted with halogen. In another preferred embodiment, x and y are0. In a particularly preferred embodiment XY₄ is X′O₄, where X′ ispreferably P or Si, more preferably P. In another particularly preferredembodiment, XY₄ is PO_(4-x)Y′_(x), where Y′ is halogen and 0<x≦1.Preferably Y′ is F (fluorine) and 0.01<x≦0.2.

In a preferred embodiment, XY₄ is PO₄ (a phosphate group) or a mixtureof PO₄ with another XY₄ group (i.e., where X′ is not P, Y′ is not O, orboth, as defined above). When part of the phosphate group issubstituted, it is preferred that the substitute group be present in aminor amount relative to the phosphate. In a preferred embodiment, XY₄comprises 80% or more phosphate and up to about 20% of one or morephosphate substitutes. Phosphate substitutes include, withoutlimitation, silicate, sulfate, antimonate, germanate, arsenate,monofluoromonophosphate, difluoromonophosphate, sulfur analogs thereof,and combinations thereof. Preferably, XY₄ comprises a maximum of about10% of a phosphate substitute or substitutes. In another preferredembodiment, XY₄ comprises a maximum of about 25% of a phosphatesubstitute or substitutes. (The percentages are based on mole percent.)Preferred XY₄ groups include those of the formula (PO₄)_(1-z) (B)_(z),where B represents an XY₄ group or combination of XY₄ groups other thanphosphate, and z≦0.5. Preferably, z≦0.8, more preferably less than aboutz≦0.2, more preferably z≦0.1.

Z is OH, halogen, or mixtures thereof. In a preferred embodiment, Z isselected from the group consisting of OH (hydroxyl), F (fluorine), Cl(chlorine), Br (bromine) and mixtures thereof. In a preferredembodiment, Z is OH. In another preferred embodiment, Z is F, ormixtures of F with OH, Cl, or Br. In one preferred embodiment, d=0. Inanother preferred embodiment, d>0, preferably from about 0.1 to about 6,more preferably from about 0.1 to about 4. In such embodiments, wherec=1, d is preferably from about 0.1 to about 3, preferably from about0.2 to about 2. In a preferred embodiment, where c=1, d is about 1.Where c=2, d is preferably from about 0.1 to about 6, preferably fromabout 1 to about 6. Where c=3, d is preferably from about 0.1 to about6, preferably from about 2 to about 6, preferably from about 3 to about6.

The composition of M¹, XY₄, Z, and the values of a, b, c, d, x and y,are selected so as to maintain electroneutrality of the electrode activematerial. As referred to herein “electroneutrality” is the state of theelectrode active material wherein the sum of the positively chargedspecies (e.g., A and M) in the material is equal to the sum of thenegatively charged species (e.g., XY₄) in the material. Preferably, theXY₄ moieties are comprised to be, as a unit moiety, an anion having acharge of −2, −3, or −4, depending on the selection of X′, X″, Y′, and xand y. When XY₄ is a mixture of groups such as the preferredphosphate/phosphate substitutes discussed above, the net charge on theXY₄ anion may take on non-integer values, depending on the charge andcomposition of the individual groups XY₄ in the mixture.

In general, the valence state of each component element of the electrodeactive material may be determined in reference to the composition andvalence state of the other component elements of the material. Byreference to the general formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d), theelectroneutrality of the material may be determined using the formula

(V ^(A))a+(V ^(M) ¹ )b+(V ^(X))c=(V ^(Y))4c+(V ^(z))d

where V^(A) is the net valence of A¹, V^(M) ¹ is the net valence of M¹,V^(Y) is the net valence of Y, and V^(z) is the net valence of Z. Asreferred to herein, the “net valence” of a component is (a) the valencestate for a component having a single element which occurs in the activematerial in a single valence state; or (b) the mole-weighted sum of thevalence states of all elements in a component comprising more than oneelement, or comprising a single element having more than one valencestate. The net valence of each component is represented in the followingformula.

(V ^(A))b=[(Val ^(A1))a ¹+(Val ^(A2))a ²+(Val ^(An))a ^(n) ]/n; a ¹ +a² + . . . a ^(n) =a

(V ^(m) ¹ )b ¹=[(V ^(M) ^(β) )b ¹+(V ^(M) ^(β) )b ²+ . . . (V ^(Mω))b^(n)]/n; b¹ +b ² + . . . b ^(n) =b

(V ^(X))c=[(V ^(X1))c ¹+(V ^(X2))c ²+ . . . (V ^(Xn))c ^(n)]/n; c¹ +c ²+. . . c^(n) =c

(V ^(Y))c=[(V ^(Y1))c ¹+(V ^(Y2))c ²+ . . . (V ^(Yn))c ^(n) ]/n; c ¹ +c² + . . . =c

(V ^(Z))d=[(V ^(Z1))d ¹+(V ^(Z2))d ²+ . . . (V ^(Zn))d ^(n)]/n; d¹ +d² + . . . d ^(n) =d

In general, the quantity and composition of M¹ is selected given thevalency of X, the value of “c,” and the amount of A, so long as M¹comprises at least one metal that is capable of oxidation. Thecalculation for the valence of M¹ can be simplified, where V^(A)=1,V^(z)=1, as follows.

For compounds where c=1: (V^(M) ¹ )b=(V^(A))4+d−a−(V^(X))

For compounds where c=3: (V^(M) ¹ )b=(V^(A))12+d−a−(V^(x))3

The values of a, b, c, d, x, and y may result in stoichiometric ornon-stoichiometric formulas for the electrode active materials. In apreferred embodiment, the values of a, b, c, d, x, and y are all integervalues, resulting in a stoichiometric formula. In another preferredembodiment, one or more of a, b, c, d, x and y may have non-integervalues. It is understood, however, in embodiments having a latticestructure comprising multiple units of a non-stoichiometric formula A¹_(a)M¹ _(b)(XY₄)_(c)Z_(d), that the formula may be stoichiometric whenlooking at a multiple of the unit. That is, for a unit formula where oneor more of a, b, c, d, x, or y is a non-integer, the values of eachvariable become an integer value with respect to a number of units thatis the least common multiplier of each of a, b, c, d, x and y. Forexample, the active material Li₂Fe_(0.5)Mg_(0.5)PO₄F isnon-stoichiometric. However, in a material comprising two of such unitsin a lattice structure, the formula is Li₄FeMg(PO₄)₂F₂.

A preferred non-stoichiometric electrode active material is of theformula Li_(1+d)M¹PO₄F_(d) where 0<d≦3, preferably 0<d≦1. Anotherpreferred non-stoichiometric electrode active material is of the formulaLi_(1+d)M′M″PO₄F_(d); where 0<d<3, preferably 0<d<1.

Another preferred embodiment comprises a compound having an olivinestructure. During charge and discharge of the battery, lithium ions areadded to, and removed from, the active material preferably withoutsubstantial changes in the crystal structure of the material. Suchmaterials have sites for the alkali metal (e.g., Li), the transitionmetal (M), and the XY₄ (e.g., phosphate) moiety. In some embodiments,all sites of the crystal structure are occupied. In other embodiments,some sites may be unoccupied, depending on, for example, the oxidationstates of the metal (M).

A preferred electrode active material embodiment comprises a compound ofthe formula

Li _(a) M ¹¹ _(b)(PO₄)Z _(d),

wherein

-   -   (i) 0.1<a≦4;    -   (ii) M¹¹ is one or more metals, comprising at least one metal        which is capable of undergoing oxidation to a higher valence        state, and 0.8≦b≦1.2;    -   (iii) Z is halogen, and 0≦d≦4; and    -   (iv) wherein M¹¹, Z, a, b, and d are selected so as to maintain        electroneutrality of said compound.    -   wherein M¹¹, Z, a, b, and d are selected so as to maintain        electroneutrality of said compound. Preferably, 0.2<a≦1.

In a preferred embodiment, M¹¹ comprises at least one element fromGroups 4 to 11 of the Periodic Table, and at least one element fromGroups 2, 3, and 12-16 of the Periodic Table. Preferably, M¹¹ isselected from the group consisting of Fe, Co, Mn, Cu, V, Cr, andmixtures thereof; and a metal selected from the group consisting of Mg,Ca, Zn, Ba, Al, and mixtures thereof. Preferably Z comprises F.Particularly preferred embodiments include those selected from the groupconsisting of Li₂Fe_(0.9)Mg_(0.1)PO4F, Li₂Fe_(0.8)Mg_(0.2)PO₄F,Li₂Fe_(0.95)Mg_(0.05)PO₄F, Li₂CoPO₄F, Li₂FePO₄F, Li₂MnPO₄F, and mixturesthereof.

Another preferred embodiment comprises a compound of the formula

LiM′_(1-j)M″_(j)PO₄,

wherein M′ is at least one transition metal from Groups 4 to 11 of thePeriodic Table and has a +2 valence state; M″ is at least one metallicelement which is from Group 2, 12, or 14 of the Periodic Table and has a+2 valence state; and 0<j<1. In a preferred embodiment compoundLiM′_(1-j)M″_(j)PO₄ has an olivine structure and 0<j≦0.2. Preferably M′is selected from the group consisting of Fe, Co, Mn, Cu, V, Cr, Ni, andmixtures thereof; more preferably M′ is selected from Fe, Co, Ni, Mn andmixtures thereof. Preferably, M″ is selected from the group consistingof Mg, Ca, Zn, Ba, and mixtures thereof. In a preferred embodiment M′ isFe and M″ is Mg.

Another preferred embodiment comprises a compound of the formula:

LiFe_(1-q)M¹² _(q)PO₄

wherein M¹² is selected from the group consisting of Mg, Ca, Zn, Sr, Pb,Cd, Sn, Ba, Be, and mixtures thereof; and 0<q<1. Preferably 0<q≦0.2. Ina preferred embodiment M¹² is selected from the group consisting of Mg,Ca, Zn, Ba, and mixtures thereof, more preferably, M¹² is Mg. In apreferred embodiment the compound comprises LiFe_(i-q)Mg_(q)PO₄, wherein0<q≦0.5. Particularly preferred embodiments include those selected fromthe group consisting of LiFe_(0.8)Mg_(0.2)PO₄, LiFe_(0.9)Mg_(0.1)PO₄,LiFe_(0.95)Mg_(0.05)PO₄, and mixtures thereof.

Another preferred embodiment comprises a compound of the formula

Li_(a)Co_(u)Fe_(y)M¹³ _(w)M¹⁴ _(aa)M¹⁵ _(bb)XY₄

wherein

-   -   (i) 0<a≦2, u>0, and v≧0;    -   (ii) M¹³ is one or more transition metals, where w≧0;    -   (iii) M¹⁴ is one or more +2 oxidation state non-transition        metals, where aa≧0;    -   (iv) M¹⁵ is one or more +3 oxidation state non-transition        metals, where bb≧0;    -   (v) XY₄ is selected from the group consisting of X′        O_(4-x)Y′_(x),    -   X′O_(4-y)Y′_(2y), X″S₄, and mixtures thereof, where X′ is        selected from the group consisting of P, As, Sb, Si, Ge, V, S,        and mixtures thereof; X″ is selected from the group consisting        of P, As, Sb, Si, Ge, V and mixtures thereof; Y′ is selected        from the group consisting of halogen, S, N, and mixtures        thereof; 0≦x≦3; and 0<y≦2; and

wherein (u+v+w+aa+bb)<2, and M¹³, M¹⁴, M¹⁵, XY₄, a, u, v, w, aa, bb, x,and y are selected so as to maintain electroneutrality of said compound.Preferably 0.8≦(u+v+w+aa+bb)≦1.2; wherein u≧0.8 and 0.05≦v≦0.15. Morepreferably, u≧0.5, 0.01≦v≦0.5, and 0.01≦w≦0.5.

In a preferred embodiment M¹³ is selected from the group consisting ofTi, V, Cr, Mn, Ni, Cu and mixtures thereof. In another preferredembodiment M¹³ is selected from the group consisting of Mn, Ti, andmixtures thereof. Preferably 0.01≦(aa+bb)≦0.5, more preferably0.01≦aa≦0.2, even more preferably 0.01≦aa≦0.1. In another preferredembodiment, M¹⁴ is selected from the group consisting of Be, Mg, Ca, Sr,Ba, and mixtures thereof. Preferably M¹⁴ is Mg and 0.01≦bb≦0.2, evenmore preferably 0.01≦bb≦0.1. In another preferred embodiment M¹⁵ isselected from the group consisting of B, Al, Ga, In, and mixturesthereof. Preferably M¹⁵ is Al. In a preferred embodiment XY₄ is PO₄.

Another preferred embodiment comprises a compound of the formula:

LiM(PO_(4-x)Y′_(x))

-   -   wherein M is M¹⁶ _(cc)M¹⁷ _(dd)M¹⁸ _(ee)M¹⁹ _(ff), and    -   (i) M¹⁶ is one or more transition metals;    -   (ii) M¹⁷ is one or more +2 oxidation state non-transition        metals;    -   (iii) M¹⁸ is one or more +3 oxidation state non-transition        metals;    -   (iv) M¹⁹ is one or more +1 oxidation state non-transition        metals;    -   (v) Y′ is halogen; and        cc>0, each of dd, ee, and ff≧0, (cc+dd+ee+ff)≦1, and 0≦x≦0.2.        Preferably cc≧0.8. Preferably 0.01≦(dd+ee)≦0.5, more preferably        0.01≦dd≦0.2 and 0.01≦ee≦0.2. In another preferred embodiment        x=0.

In a preferred embodiment M¹⁶ is a +2 oxidation state transition metalselected from the group consisting of V, Cr, Mn, Fe, Co, Cu, andmixtures thereof. In another preferred embodiment, M¹⁶ is selected fromthe group consisting of Fe, Co, and mixtures thereof. In a preferredembodiment M¹⁷ is selected from the group consisting of Be, Mg, Ca, Sr,Ba and mixtures thereof. In a preferred embodiment M¹⁸ is Al. In apreferred embodiment, M¹⁹ is selected from the group consisting of Li,Na, and K, wherein 0.01≦ff≦0.2. In another preferred embodiment M¹⁹ isLi. In another preferred embodiment, wherein x=0, (cc+dd+ee+ff)=1, M¹⁷is selected from the group consisting of Be, Mg, Ca, Sr, Ba and mixturesthereof, preferably 0.01≦dd≦0.1, M¹⁸ is Al, preferably 0.01≦ee≦0.1, andM¹⁹ is Li, preferably 0.01≦ff≦0.1. In another preferred embodiment,0<x≦0, even more preferably 0.01≦x≦0.05, and (cc+dd+ee+ff)<1, whereincc≧0.8, 0.01≦dd≦0.1, 0.01≦ee≦0.1 and ff=0. Preferably (cc+dd+ee)=1−x.

Another preferred embodiment comprises a compound of the formula:

A¹ _(a)(MO)_(b)M_(1-b)X^(O) ₄

-   -   (i) A¹ is independently selected from the group consisting of        Li, Na, K and mixtures thereof, 0.1<a<2;    -   (ii) M comprises at least one element, having a +4 oxidation        state, capable of being oxidized to a higher oxidation state;        0<b≦1;    -   (iii) M′ is one or more metals selected from metals having a +2        and a +3 oxidation state; and    -   (iv) X is selected from the group consisting of P, As, Sb, Si,        Ge, V, S, and mixtures thereof.

In a preferred embodiment, A¹ is Li. In another preferred embodiment, Mis selected from a group consisting of +4 oxidation state transitionmetals. Preferably M is selected from the group comprising Vanadium (V),Tantalum (Ta), Niobium (Nb), molybdenum (Mo), and mixtures thereof. In apreferred embodiment M comprises V, b=1. M′ may generally be any +2 or+3 element, or mixture of elements. In a preferred embodiment, M′ isselected from the group consisting V, Cr, Mn, Fe, Co, Ni, Mo, Ti, Al,Ga, In, Sb, Bi, Sc, and mixtures thereof. More preferably M′ is V, Cr,Mn, Fe, Co, Ni, Ti, Al, and mixtures thereof. In one embodiment, M′comprises Al. Particularly preferred embodiments include those selectedfrom the group consisting of LiVOPO₄, Li(VO)_(0.75)Mn_(0.25)PO₄,Li_(0.75)Na_(0.25)VOPO₄, and mixtures thereof.

Another preferred embodiment comprises a compound of the formula:

A¹ _(a)M¹ _(b)(XY₄)₃Z_(d),

wherein

-   -   (a) A is selected from the group consisting of Li, Na, K, and        mixtures thereof, and 2≦a≦8;    -   (b) M comprises one or more metals, comprising at least one        metal which is capable of undergoing oxidation to a higher        valence state, and 1≦b≦3;    -   (c) XY₄ is selected from the group consisting of        X′O_(4-x)Y′_(x), X′O_(4-y)Y′_(2y), X″S₄, and mixtures thereof,        where X′ is selected from the group consisting of P, As, Sb, Si,        Ge, V, S, and mixtures thereof; X″ is selected from the group        consisting of P, As, Sb, Si, Ge, V, and mixtures thereof; Y′ is        selected from the group consisting of halogen, S, N, and        mixtures thereof; 0≦x<3; and 0<y<2; and    -   (d) Z is OH, halogen, or mixtures thereof, and 0≦d≦6; and        wherein M¹, XY₄, Z, a, b, d, x and y are selected so as to        maintain electroneutrality of said compound.

In a preferred embodiment, A comprises Li, or mixtures of Li with Na orK. In another preferred embodiment, A comprises Na, K, or mixturesthereof. In a preferred embodiment, M¹ comprises two or more transitionmetals from Groups 4 to 11 of the Periodic Table, preferably transitionmetals selected from the group consisting of Fe, Co, Ni, Mn, Cu, V, Zr,Ti, Cr, and mixtures thereof. In another preferred embodiment, M¹comprises M′_(1-m)M″_(m), where M′ is at least one transition metal fromGroups 4 to 11 of the Periodic Table; and M″ is at least one elementfrom Groups 2, 3, and 12-16 of the Periodic Table; and 0<m<1.Preferably, M′ is selected from the group consisting of Fe, Co, Ni, Mn,Cu, V, Zr, Ti, Cr, and mixtures thereof; more preferably M′ is selectedfrom the group consisting of Fe, Co, Mn, Cu, V, Cr, and mixturesthereof. Preferably, M″ is selected from the group consisting of Mg, Ca,Zn, Sr, Pb, Cd, Sn, Ba, Be, Al, and mixtures thereof; more preferably,M″ is selected from the group consisting of Mg, Ca, Zn, Ba, Al, andmixtures thereof. In a preferred embodiment, XY₄ is PO₄. In anotherpreferred embodiment, X′ comprises As, Sb, Si, Ge, S, and mixturesthereof; X″ comprises As, Sb, Si, Ge and mixtures thereof; and 0<x<3. Ina preferred embodiment, Z comprises F, or mixtures of F with Cl, Br, OH,or mixtures thereof. In another preferred embodiment, Z comprises OH, ormixtures thereof with Cl or Br.

Non-limiting examples of active materials of the invention include thefollowing: Li_(0.95)Co_(0.8)Fe_(0.15)Al_(0.05)PO₄,Li_(1.025)Co_(0.85)Fe_(0.05)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.80)Fe_(0.10)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.45)Fe_(0.45)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.75)Fe_(0.15)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.7)(Fe_(0.4)Mn_(0.6))_(0.2)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.75)Fe_(0.15)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.85)Fe_(0.05)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.7)Fe_(0.08)Mn_(0.12)Al_(0.025)Mg_(0.05)PO₄,LiCu_(0.75)Fe_(0.15)Al_(0.025)Ca_(0.05)PO_(3.975)F_(0.025),LiCo_(0.80)Fe_(0.10)Al_(0.025)Ca_(0.05)PO_(3.975)F_(0.025),Li_(1.25)Co_(0.6)Fe_(0.1) Mn_(0.075)Mg_(0.025)Al_(0.05)PO₄,Li_(1.0)Na_(0.25)Co_(0.6)Fe_(0.1)Cu_(0.075)Mg_(0.025)Al_(0.05)PO₄,Li_(1.025)Co_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.075)PO₄,Li_(1.025)Co_(0.6)Fe_(0.05)Al_(0.12)Mg_(0.0325)PO_(3.75)F_(0.25),Li_(1.025)Co_(0.7)Fe_(0.1)Mg_(0.0025)Al_(0.04)PO_(3.75)F_(0.25),Li_(0.75)Co_(0.5)Fe_(0.05)Mg_(0.015)Al_(0.04)PO₃F,Li_(0.75)Cu_(0.5)Fe_(0.025)Cu_(0.025)Be_(0.015)Al_(0.04)PO₃F,Li_(0.75)Co_(0.5)Fe_(0.025)Mn_(0.025)Ca_(0.015)Al_(0.04)PO₃F,Li_(1.025)Co_(0.6)Fe_(0.05)B_(0.12)Ca_(0.0325)PO_(3.75)F_(0.25),Li_(1.025)Co_(0.65)Fe_(0.05)Mg_(0.0125)Al_(0.1)PO_(3.75)F_(0.25),Li_(1.025)Co_(0.65)Fe_(0.05)Mg_(0.065)Al_(0.14)PO_(3.975)F_(0.025),Li_(1.075)Co_(0.8)Fe_(0.05)Mg_(0.025)Al_(0.05)PO_(3.975)F_(0.025),LiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025),Li_(0.25)Fe_(0.7)Al_(0.45)PO₄, LiMnAl_(0.067)(PO₄)_(0.8)(SiO₄)_(0.2),Li_(0.95)Co_(0.9)Al_(0.05)Mg_(0.05)PO₄,Li_(0.95)Fe_(0.8)Ca_(0.15)Al_(0.05)PO₄,Li_(0.25)MnBe_(0.425)Ga_(0.3)SiO₄,Li_(0.5)Na_(0.25)Mn_(0.6)Ca_(0.375)Al_(0.1)PO₄,Li_(0.25)Al_(0.25)Mg_(0.25)Co_(0.75)PO₄,Na_(0.55)B_(0.15)Ni_(0.75)Ba_(0.25)PO₄,Li_(1.025)Co_(0.9)Al_(0.025)Mg_(0.05)PO₄;K_(1.025)Ni_(0.09)Al_(0.025)Ca_(0.05)PO₄,L_(0.95)Co_(0.9)Al_(0.05)Mg_(0.05)PO₄,Li_(0.95)Fe_(0.8)Ca_(0.15)Al_(0.05)PO₄,Li_(1.025)Co_(0.7)(Fe_(0.4)Mn_(0.6))_(0.2)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.9)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.75)Fe_(0.15)Al_(0.025)Mg_(0.025)PO₄,LiCo_(0.75)Fe_(0.15)Al_(0.025)Ca_(0.05)PO_(3.975)F_(0.025),LiCo_(0.9)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025),Li_(0.75)Co_(0.625)Al_(0.25)PO_(3.75)F_(0.25),Li_(1.075)Fe_(0.8)Mg_(0.075)Al_(0.05)PO_(3.975)F_(0.025),Li_(1.075)Co_(0.8)Mg_(0.075)Al_(0.05)PO_(3.975)F_(0.025),Li_(1.025)Co_(0.8)Mg_(0.1)Al_(0.05)PO_(3.975)F_(0.025),Li_(1.025)Co_(0.8)Mg_(0.1)Al_(0.05)PO_(3.975)F_(0.025),LiCo_(0.7)Fe_(0.2)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025),Li₂Fe_(0.8)Mg_(0.2)PO₄F; Li₂Fe_(0.5)Co_(0.5)PO₄F; Li₃CoPO₄F₂;KFe(PO₃F)F; Li₂Co(PO₃F)Br₂; Li₂Fe(PO₃F₂)F; Li₂FePO₄Cl; Li₂MnPO₄OH;Li₂CoPO₄F; Li₂Fe_(0.5)Co_(0.5)PO₄F; Li₂Fe_(0.9)Mg_(0.1)PO₄F;Li₂Fe_(0.8)Mg_(0.2)PO₄F; Li_(1.25)Fe_(0.9)Mg_(0.1)PO₄F_(0.25);Li₂MnPO₄F; Li₂CoPO₄F; K₂Fe_(0.9)Mg_(0.1)P_(0.5)As_(0.5)O₄F; Li₂MnSbO₄OH;Li₂Fe_(0.6)Co_(0.4)SbO₄Br; Na₃CoAsO₄F₂; LiFe(AsO₃F)Cl;Li₂Co(As_(0.5)Sb_(0.5)O₃F)F₂; K₂Fe(AsO₃F₂)F; Li₂NiSbO₄F; Li₂FeAsO₄OH;Li₄Mn₂(PO₄)₃F; Na₄FeMn(PO₄)₃OH; Li₄FeV(PO₄)₃Br; Li₃VA1(PO₄)₃F;K₃VA1(PO₄)₃Cl; LiKNaTiFe(PO₄)₃F; Li₄Ti₂(PO₄)₃Br; Li₃V₂(PO₄)₃F₂;Li₆FeMg(PO₄)₃OH; Li₄Mn₂(AsO₄)₃F; K₄FeMn(AsO₄)₃OH;Li₄FeV(P_(0.5)Sb_(0.5)O₄)₃Br; LiNaKAlV(AsO₄)₃F; K₃VA1(SbO₄)₃Cl;Li₃TiV(SbO₄)₃F; Li₂FeMn(P_(0.5)As_(0.5)O₃F)₃; Li₄Ti₂(PO₄)₃F;Li_(3.25)V₂(PO₄)₃F_(0.25); Li₃Na_(0.75)Fe₂(PO₄)₃F_(0.75);Na_(6.5)Fe₂(PO₄)₃(OH)Cl_(0.5); K₈Ti₂(PO₄)₃F₃Br₂; K₈Ti₂(PO₄)₃F₅;Li₄Ti₂(PO₄)₃F; Na_(1.25)Ti₂(PO₄)₃F_(0.5)Cl_(0.75);K_(3.25)Mn₂(PO₄)₃OH_(0.25); LiNa_(1.25)KTiV(PO₄)₃ (OH)_(1.25)Cl;Na₈Ti₂(PO₄)₃F₃Cl₂; Li₇Fe₂(PO₄)₃F₂; Li₈FeMg(PO₄)₃F_(2.25)Cl_(0.75);Li₅Na_(2.5)TiMn(PO₄)₃(OH)₂Cl_(0.5); Na₃K_(4.5)MnCa(PO₄)₃(OH)_(1.5)Br;K₉FeBa(PO₄)₃F₂Cl₂; Li₇Ti₂(SiO₄)₂(PO₄)F₂; Na₈Mn₂(SiO₄)₂(PO₄)F₂Cl;Li₃K₂V₂(SiO₄)₂(PO₄)(OH)Cl; Li₄Ti₂(SiO₄)₂(PO₄)(OH);Li₂NaKV₂(SiO₄)₂(PO₄)F; Li₅TiFe(PO₄)₃F; Na₄K₂VMg(PO₄)₃FCl;Li₄NaAlNi(PO₄)₃(OH); Li₄K₃FeMg(PO₄)₃F₂; Li₂Na₂K₂CrMn(PO₄)₃(OH)Br;Li₄TiCa(PO₄)₃F; Li₄Ti_(0.75)Fe_(1.5)(PO₄)₃F; Li₃NaSnFe(PO₄)₃(OH);Li₃NaGe_(0.5)Ni₂(PO₄)₃(OH); Na₃K₂VCo(PO₄)₃(OH)Cl; Li₄Na₂MnCa(PO₄)₃F(OH);Li₃NaKTiFe(PO₄)₃F; Li₇FeCo(SiO₄)₂(PO₄)F; Li₃Na₃TiV(SiO₄)₂(PO₄)F;K_(5.5)CrMn(SiO₄)₂(PO₄)Cl_(0.5); Li₃Na_(2.5)V₂(SiO₄)₂(PO₄)(OH)_(0.5);Na_(5.25)FeMn(SiO₄)₂(PO₄)Br_(0.25); Li_(6.5)VCo(SiO₄)_(2.5)(PO₄)_(0.5)F;Na_(7.25)V₂(SiO₄)_(2.25)(Pa₄)_(0.75)F₂; Li₄NaVTi(SiO₄)₃F_(0.5)Cl_(0.5);Na₂K_(2.5)ZrV(SiO₄)₃F_(0.5); Li₄K₂MnV(SiO₄) ₃(OH)₂; Li₃Na₃KTi₂(SiO₄)₃F;K₆V₂(SiO₄)₃(OH)Br; Li₈FeMn(SiO₄)₃F₂; Na₃K_(4.5)MnNi(SiO₄)₃(OH)_(1.5);Li₃Na₂K₂TiV(SiO₄)₃ (OH)_(0.5)Cl_(0.5); K₉VCr(SiO₄)₃F₂Cl;Li₄Na₄V₂(SiO₄)₃FBr; Li₄FeMg(SO₄)₃F₂; Na₂KNiCo(SO₄)₃(OH);Na₅MnCa(SO₄)₃F₂Cl; Li₃NaCoBa(S O₄)₃FBr; Li_(2.5)K_(0.5)FeZn(SO₄)₃F;Li₃MgFe(SO₄)₃F₂; Li₂NaCaV(SO₄)₃FCl; Na₄NiMn(SO₄)₃ (OH)₂;Na₂KBaFe(SO₄)₃F; Li₂KCuV(SO₄)₃(OH)Br; Li_(1.5)CoPO₄F_(0.5);Li_(1.25)CoPO₄F_(0.25); Li_(1.75)FePO₄F_(0.75); Li_(1.66)MnPo₄F_(0.66);Li_(1.5)Co_(0.75)Ca_(0.25)PO₄F_(0.5);Li_(1.75)Co_(0.8)Mn_(0.2)PO₄F_(0.75);Li_(1.25)Fe_(0.75)Mg_(0.25)PO₄F_(0.25);Li_(1.66)Co_(0.6)Zn_(0.4)PO₄F_(0.66); KMn₂SiO₄Cl; Li₂VSiO₄(OH)₂;Li₃CoGeO₄F; LiMnSO₄F; NaFe_(0.9)Mg_(0.1)SO₄Cl; LiFeSO₄F; LiMnSO₄OH;KMnSO₄F; Li_(1.75)Mn_(0.8)Mg_(0.2)PO₄F_(0.75); Li₃FeZn(PO₄)F₂;Li_(0.5)V_(0.75)Mg_(0.5)(PO₄)F_(0.75); Li₃V_(0.5)Al_(0.5) (PO₄)F_(3.5);Li_(0.75)VCa(PO₄)F_(1.75); Li₄CuBa(PO₄)F₄;Li_(0.5)V_(0.5)Ca(PO₄)(OH)_(1.5); Li_(1.5)FeMg(PO₄)(OH)Cl;LiFeCoCa(PO₄)(OH)₃F; Li₃CoBa(PO₄)(OH)₂Br₂;Li_(0.75)Mn_(1.5)Al(PO₄)(OH)_(3.75); Li₂Co_(0.75)Mg_(0.25)(PO₄)F;LiNaCo_(0.8)Mg_(0.2)(PO₄)F; NaKCo_(0.5)Mg_(0.5) (PO₄)F;LiNa_(0.5)K_(0.5)Fe_(0.75)Mg_(0.25)(PO₄)F;Li_(1.5)K_(0.5)V_(0.5)Zn_(0.5)(PO₄)F₂; Na₆Fe₂Mg(PS₄)₃(OH₂)Cl;Li₄Mn_(1.5)Co_(0.5)(PO₃F)₃(OH)_(3.5); K₈FeMg(PO₃F)₃F₃Cl₃Li₅Fe₂Mg(SO₄)₃Cl₅; LiTi₂(SO₄)₃Cl, LiMn₂(SO₄)₃F, Li₃Ni₂(SO₄)₃Cl,Li₃Co₂(SO₄)₃F, Li₃Fe₂(SO₄)₃Br, Li₃Mn₂(SO₄)₃F, Li₃MnFe(SO₄)₃F,Li₃NiCo(SO₄)₃Cl; LiMnSO₄F; LiFeSO₄Cl; LiNiSO₄F; LiCoSO₄Cl;LiMn_(1-x)Fe_(x)SO₄F, LiFe_(1-x)Mg_(x)SO₄F; Li₇ZrMn(SiO₄)₃F;Li₇MnCo(SiO₄)₃F; Li₇MnNi(SiO₄)₃F; Li₇VA1(SiO₄)₃F; Li₅MnCo(PO₄)₂(SiO₄)F;Li₄VA1(PO₄)₂(SiO₄)F; Li₄MnV(PO₄)₂(SiO₄)F; Li₄VFe(PO₄)₂(SiO₄)F;Li_(0.6)VPO₄F_(0.6); Li_(0.8)VPO₄F_(0.8); LiVPO₄F; Li₃V₂(PO₄)₂F₃;LiVPO₄Cl; LiVPO₄OH; NaVPO₄F; Na₃V₂(PO₄)₂F₃; LiV_(0.9)Al_(0.1)PO₄F;LiFePO₄F; LiTiPO₄F; LiCrPO₄F; LiFePO₄; LiCoPO₄, LiMnPO₄;LiFe_(0.9)Mg_(0.1)PO₄; LiFe_(0.8)Mg_(0.2)PO₄; LiFe_(0.95)Mg_(0.05)PO₄;LiFe_(0.9)Ca_(0.1)PO₄; LiFe_(0.8)Ca_(0.2)PO₄; LiFe_(0.8)Zn_(0.2)PO₄;LiMn_(0.8)Fe_(0.2)PO₄; LiMn_(0.9)Fe_(0.8)PO₄; Li₃V₂(PO₄)₃; Li₃Fe₂(PO₄)₃;Li₃Mn₂(PO₄)₃; Li₃FeTi(PO₄)₃; Li₃CoMn(PO₄)₃; Li₃FeV(PO₄)₃; Li₃VTi(PO₄)₃;Li₃FeCr(PO₄)₃; Li₃FeMo(PO₄)₃; Li₃FeNi(PO₄)₃; Li₃FeMn(PO₄)₃;Li₃FeAl(PO₄)₃; Li₃FeCo(PO₄)₃; Li₃Ti₂(PO₄)₃; Li₃TiCr(PO₄)₃;Li₃TiMn(PO₄)₃; Li₃TiMo(PO₄)₃; Li₃TiCo(PO₄)₃; Li₃TiAl(PO₄)₃;Li₃TiNi(PO₄)₃; Li₃ZrMnSiP₂O₁₂; Li₃V₂SiP₂O₁₂; Li₃MnVSiP₂O₁₂;Li₃TiVSiP₂O₁₂; Li₃TiCrSiP₂O₁₂; Li_(3.5)AlVSi_(0.5)P_(2.5)O₁₂;Li_(3.5)V2Si_(0.5)P_(2.5)O₁₂; Li_(2.5)AlCrSi_(0.5)P_(2.5)O₁2;Li_(2.5)V₂P₃O_(11.5)F_(0.5); Li₂V₂P₃O₁₁F; Li_(2.5)VMnP₃O_(11.5)F_(0.5);Li₂V_(0.5)Fe_(1.5)P₃O₁₁F; Li₃V_(0.5)V_(1.5)P₃O_(11.5)F_(0.5);Li₃V₂P₃O₁₁F; Li₃Mn_(0.5)V_(1.5)P₃O₁₁F_(0.5);LiCo_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.05)PO₄;Li_(1.025)Co_(0.8)Fe_(0.1)Ti_(0.025)Al_(0.025)PO₄;Li_(1.025)Co_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.025)PO_(3.975)F_(0.025);LiCo_(0.825)Fe_(0.1)Ti_(0.025)Mg_(0.025)PO₄;LiCo_(0.85)Fe_(0.075)Ti_(0.025)Mg_(0.025)PO₄;LiCo_(0.8)Fe_(0.1)Ti_(0.025)Al_(0.025)Mg_(0.025)PO₄,Li_(1.025)Co_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.8)Fe_(0.1)Ti_(0.025)Al_(0.025)Mg_(0.025)PO₄,LiCu_(0.8)Fe_(0.1)Ti_(0.05)Mg_(0.05)PO₄, LiVOPO₄,Li(VO)_(0.75)Mn_(0.25)PO₄, NaVOPO₄, Li_(0.75)Na_(0.25)VOPO₄,Li(VO)_(0.5)Al_(0.5)PO₄, Na(VO)_(0.75)Fe_(0.25)PO₄,Li_(0.5)Na_(0.5)VOPO₄, Li(VO)_(0.75)Co_(0.25)PO₄,Li(VO)_(0.75)Mo_(0.25)PO₄, LiVOSO₄, and mixtures thereof.

Preferred active materials include LiFePO₄; LiCoPO₄, LiMnPO₄;LiMn_(0.8)Fe_(0.2)PO₄; LiMn_(0.9)Fe_(0.8)PO₄; LiFe_(0.9)Mg_(0.1)PO₄;LiFe_(0.8)Mg_(0.2)PO₄; LiFe_(0.95)Mg_(0.05)PO₄;Li_(1.025)Co_(0.85)Fe_(0.05)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.80)Fe_(0.10)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.75)Fe_(0.15)Al_(0.025)Mg_(0.05)PO₄, Li_(1.025)Co_(0.7)(Fe_(0.4)Mn_(0.6))_(0.2)Al_(0.025) Mg_(0.05)PO₄,LiCu_(0.8)Fe_(0.1)Al_(0.025)Ca_(0.05)PO_(3.975)F_(0.025),LiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025),LiCo_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.05)PO₄;Li_(1.025)Co_(0.8)Fe_(0.1)Ti_(0.025)Al_(0.025)PO₄;Li_(1.025)Co_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.025)PO_(3.975)F_(0.025);LiCo_(0.825)Fe_(0.1)Ti_(0.025)Mg_(0.025)PO₄;LiCo_(0.85)Fe_(0.075)Ti_(0.025)Mg_(0.025)PO₄; LiVOPO₄;Li(VO)_(0.75)Mn_(0.25)PO₄; and mixtures thereof. A particularlypreferred active material isLiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025).

II. A_(e)M_(f)O_(g) Active Materials:

In an embodiment of this invention, active materials of this inventioncomprise alkali metal transition metal oxides of the formulaA_(e)M_(f)O_(g). Such embodiments comprise compounds of the formula A²_(e)M³ _(f)O_(g).

A² is selected from the group consisting of Li (lithium), Na (sodium), K(potassium), and mixtures thereof. In a preferred embodiment, A² is Li,or a mixture of Li with Na, a mixture of Li with K, or a mixture of Li,Na and K. In another preferred embodiment, A² is Na, or a mixture of Nawith K. Preferably “e” is from about 0.1 to about 6, more preferablyfrom about 0.1 to about 3, and even more preferably from about 0.2 toabout 2.

M³ comprises one or more metals, comprising at least one metal which iscapable of undergoing oxidation to a higher valence state. In apreferred embodiment, removal of alkali metal from the electrode activematerial is accompanied by a change in oxidation state of at least oneof the metals comprising M³. The amount of the metal that is availablefor oxidation in the electrode active material determined the amount ofalkali metal that may be removed. Such concepts for oxide activematerials are well known in the art, e.g., as disclosed in U.S. Pat.Nos. 4,302,518 and 4,357,215 issued to Goodenough et al; and U.S. Pat.No. 5,783,333, Mayer, issued Jul. 21, 1998, all of which areincorporated by reference herein.

Similar to the oxidation process described above for formula

A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d), the oxidation process for A² _(e)M³_(f)O_(g) reflects the amount (e′) of alkali metal that can be removed,as a function of the quantity (f′) and valency (V^(M) ² ) of oxidizablemetal, is

e′=f′(ΔV ^(M) ³ ),

where ΔV^(M) ² is the difference between the valence state of the metalin the active material and a valence state readily available for themetal.

The O_(g) component of the compound provides the oxide and thenegatively charged species in the material. Preferably 1≦g≦15, morepreferably 2≦g≦13, and even more preferably 2≦g≦8.

M³ may comprise a single metal, or a combination of two or more metals.In embodiments where M³ is a combination of elements, the total valenceof M² in the active material must be such that the resulting activematerial is electrically neutral. M³ may be, in general, a metal ormetalloid, selected from the group consisting of elements from Group2-14 of the Periodic Table.

Transition metals useful herein include those selected from the groupconsisting of Ti (Titanium), V (Vanadium), Cr (Chromium), Mn(Manganese), Fe (Iron), Co (Cobalt), Ni (Nickel), Cu (Copper), Zr(Zirconium), Nb (Niobium), Mo (Molybdenum), Ru (Ruthenium), Rh(Rhodium), Pd (Palladium), Ag (Silver), Cd (Cadmium), Hf (Hafnium), Ta(Tantalum), W (Tungsten), Re (Rhenium), Os (Osmium), Ir (Iridium), Pt(Platinum), Au (Gold), Hg (Mercury), and mixtures thereof. Preferred arethe first row transition series (the 4th Period of the Periodic Table),selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, andmixtures thereof. Particularly preferred transition metals useful hereinclude Fe, Co, Mn, Mo, Cu, V, Cr, and mixtures thereof. In someembodiments, mixtures of transition metals are preferred. Although, avariety of oxidation states for such transition metals are available, insome embodiments it is preferred that the transition metals have a +2oxidation state.

M³ may also comprise non-transition metals and metalloids. Among suchelements are those selected from the group consisting of Group 2elements, particularly Be (Beryllium), Mg (Magnesium), Ca (Calcium), Sr(Strontium), Ba (Barium); Group 3 elements, particularly Sc (Scandium),Y (Yttrium), and the lanthanides, particularly La (Lanthanum), Ce(Cerium), Pr (Praseodymium), Nd (Neodymium), Sm (Samarium); Group 12elements, particularly Zn (zinc) and Cd (cadmium); Group 13 elements,particularly B (Boron), Al (Aluminum), Ga (Gallium), In (Indium), Tl(Thallium); Group 14 elements, particularly Si (Silicon), Ge(Germanium), Sn (Tin), and Pb (Lead); Group 15 elements, particularly As(Arsenic), Sb (Antimony), and Bi (Bismuth); Group 16 elements,particularly Te (Tellurium); and mixtures thereof. Preferrednon-transition metals include the Group 2 elements, Group 12 elements,Group 13 elements, and Group 14 elements. Particularly preferrednon-transition metals include those selected from the group consistingof Mg, Ca, Zn, Sr, Pb, Cd, Sn, Ba, Be, Al, and mixtures thereof.Particularly preferred are non-transition metals selected from the groupconsisting of Mg, Ca, Zn, Ba, Al, and mixtures thereof.

In a preferred embodiment, M³ comprises one or more transition metalsfrom Groups 4 to 11. In another preferred embodiment, M³ comprises amixtures of metals, wherein is at least one is a transition metal fromGroups 4 to 11. In another preferred embodiment, M³ comprises at leastone metal selected from the group consisting of Fe, Co, Ni, V, Zr, Ti,Mo and Cr, preferably 1≦f≦6. In another preferred embodiment M² is M⁴_(k)M⁵ _(m)M⁶ _(n), wherein k+m+n=f. In a preferred embodiment, M⁴ is atransition metal selected from the group consisting of Fe, Co, Ni, Mo,Cu, V, Zr, Ti, Cr, Mo and mixtures thereof, more preferably M⁴ isselected from the group consisting of Co, Ni, Mo, V, Ti, and mixturesthereof. In a preferred embodiment, M⁵ is one or more transition metalfrom Groups 4 to 11 of the Periodic Table. In a preferred embodiment, M⁶is at least one metal selected from Group 2, 12, 13, or 14 of thePeriodic Table, more preferably M⁶ is selected from the group consistingof Mg, Ca, Al, and mixtures thereof, preferably n>0.

A preferred electrode active material embodiment comprises a compound ofthe formula A² _(e)M² _(f)O_(g). In a preferred embodiment A² comprisesLi. Preferably M² comprises one or more metals, wherein at least onemetal is capable of undergoing oxidation to a higher valence state, and1≦f≦6. In another preferred embodiment M² is M⁴ _(k)M⁵ _(m)M⁶ _(n),wherein k+m+n=f. In a preferred embodiment, M⁴ is a transition metalselected from the group consisting of Fe, Co, Ni, Mo, V, Zr, Ti, Cr, andmixtures thereof, more preferably M⁴ is selected from the groupconsisting of Co, Ni, Mo, V, Ti, and mixtures thereof. In a preferredembodiment, M⁵ is one or more transition metal from Groups 4 to 11 ofthe Periodic Table. In a preferred embodiment, M⁶ is at least one metalselected from Group 2, 12, 13, or 14 of the Periodic Table, morepreferably M⁶ is selected from the group consisting of Mg, Ca, Al, andmixtures thereof, preferably n>0.

A preferred electrode active material embodiment comprises a compound ofthe formula

LiNi_(r)Co_(s)M⁶ _(t)O₂

wherein 0<(r+s)≦1, and 0≦t<1. In another preferred embodiment r=(1−s),where t=0. In another preferred embodiment r=(1−s−t), wherein t>0. M⁶ isat least one metal selected from Group 2, 12, 13, or 14 of the PeriodicTable, more preferably M⁶ is selected from the group consisting of Mg,Ca, Al, and mixtures thereof.

Alkali/transition metal oxides among those useful herein includeLiMn₂O₄, LiNiO₂, LiCoO₂, LiNi_(0.75)Al_(0.25)O₂, Li₂CuO₂, γ-LiV₂O₅,LiCo_(0.5)Ni_(0.5)O₂, NaCoO₂, NaNiO₂, LiNiCoO₂, LiNi_(0.75)Co_(0.25)O₂,LiNi_(0.8)Co_(0.2)O₂, LiNi_(0.6)Co_(0.4)O₂, LiMnO₂, LiMoO₂,LiNi_(0.8)Co_(0.15)Al_(0.05)O₂, LiFeO₃, α-LiFe₅O₈, β-LiFe₅O₈, Li₂Fe₃O₄,LiFe₂O₃, LiNi_(0.6)Co_(0.2)Al_(0.2)O₂, LiNi_(0.8)Co_(0.15)Mg_(0.05)O₂,LiNi_(0.8)Co_(0.15)Ca_(0.05)O₂, NaNi_(0.8)Co_(0.15)Al_(0.05)O₂,KNi_(0.8)Co_(0.15)Mg_(0.05)O₂, LiCr_(0.8)Co_(0.15)Al_(0.05)O₂, KCoO₂,Li_(0.5)Na_(0.5)CoO₂, NaNi_(0.6)Co_(0.4)O₂,KNi_(0.75)Co_(0.25)O₂,Fe_(0.75)Co_(0.25)O₂, LiCU_(0.8)Co_(0.2)O₂,LiTi_(0.9)Ni_(0.1)O₂, LiV_(0.8)Co_(0.2)O2, Li₃V₂Co_(0.5)Al_(0.5)O₅,Na₂UVNi_(0.5)Mg_(0.5)O₅, Li₅CrFe_(1.5)CaO₇, LiCrO₂, LiVO₂, LiTiO₂,NaVO₂, NaTiO₂, Li₂FeV₂O₅, Li₅Ni_(2.5)Co₃O₈; Li₆V₂Fe_(1.5)CaO₉, andmixtures thereof. Preferred alkali/transition metal oxides includeLiNiO₂, LiCoO₂, LiNi_(1-x)Co₃O₂, γ-LiV₂O₅, Li₂CuO₂ and mixtures thereof.

Another preferred embodiment of this invention comprises electrodeactive materials of the formula A³ _(h)Mn_(i)O (herein “modifiedmanganese oxide”) having an inner and an outer region, wherein the innerregion comprises a cubic spinel manganese oxide, and the outer region isenriched with Mn⁺⁴ relative to the inner region.

In a preferred embodiment A³ is selected from the group consisting of Li(lithium), Na (sodium), K (potassium), and mixtures thereof. In apreferred embodiment, A³ is Li, or a mixture of Li with Na, a mixture ofLi with K, or a mixture of Li, Na and K. In another preferredembodiment, A³ is Na, or a mixture of Na with K. Preferably h≦2.0, morepreferably 0.8≦h≦1.5, and even more preferably 0.8≦h≦1.2, and h and iare selected so as to maintain electroneutrality.

In a preferred embodiment, such modified manganese oxide activematerials are characterized as particles having a core or bulk structureof cubic spinel manganese oxide and a surface region which is enrichedin Mn⁺⁴ relative to the bulk. X-ray diffraction data and x-rayphotoelectron spectroscopy data are consistent with the structure of thestabilized manganese oxide being a central bulk of cubic spinel lithiummanganese oxide with a surface layer or region comprising A₂MnO₃, whereA is an alkali metal.

The mixture preferably contains less than 50% by weight of the alkalimetal compound, preferably less than about 20%. The mixture contains atleast about 0.1% by weight of the alkali metal compound, and preferably1% by weight or more. In a preferred embodiment, the mixture containsfrom about 0.1% to about 20%, preferably from about 0.1% to about 10%,and more preferably from about 0.4% to about 6% by weight of the alkalimetal compound.

The alkali metal compound is a compound of lithium, sodium, potassium,rubidium or cesium. The alkali metal compound serves as a source ofalkali metal ion in particulate form. Preferred alkali metal compoundsare sodium compounds and lithium compounds. Examples of compoundsinclude, without limitation, carbonates, metal oxides, hydroxides,sulfates, aluminates, phosphates and silicates. Examples of lithiumcompounds thus include, without limitation, lithium carbonates, lithiummetal oxides, lithium mixed metal oxides, lithium hydroxides, lithiumaluminates, and lithium silicates, while analogous sodium compounds arealso preferred. A preferred lithium compound is lithium carbonate.Sodium carbonate and sodium hydroxide are preferred sodium compounds.The modified manganese oxide is preferably characterized by reducedsurface area and increased alkali metal content compared to anunmodified spinel lithium manganese oxide. In one alternative,essentially all of a lithium or sodium compound is decomposed or reactedwith the lithium manganese oxide.

In one aspect, the decomposition product is a reaction product of theLMO particles and the alkali metal compound. For the case where thealkali metal is lithium, a lithium-rich spinel is prepared. A preferredelectrode active material embodiment comprises a compound of the formulaLi_(i+p)Mn_(2−p)O₄, where 0≦p<0.2. Preferably p is greater than or equalto about 0.081.

In many embodiments, the modified manganese oxide material of theinvention is red in color. Without being bound by theory, the red colormay be due to a deposit or nucleation of Li₂MnO₃ (or Na₂MnO₃, which isalso red in color) at the surface or at the grain boundaries. Withoutbeing bound by theory, one way to envision the formation of the “red”modified manganese oxide is as follows. Mn⁺³ at the surface of a cubicspinel lithiated manganese oxide particle loses an electron to combinewith added alkali metal from the alkali metal compound. Advantageously,the alkali metal compound is lithium carbonate. Thus, the cubic spinellithiated manganese oxide becomes enriched in lithium. Charge balance ismaintained by combination with oxygen from the available atmosphere,air, during the solid state synthesis. The oxidation of Mn⁺³ to Mn⁺⁴ atthe surface of the particle results in a loss of available capacity anda contraction of the unit cell. Thus a surface region of the particlerelatively enhanced in Mn⁺⁴ forms during the reaction of the cubicspinel lithiated manganese oxide with the lithium compound in air or inthe presence of oxygen. At least in the early stages of the reaction, asurface layer or coating of Li₂MnO₃ is formed on the surface of theparticle. It is believed that formation of the red colored Li₂MnO₃ (orNa₂MnO₃) at the surface of the particle is responsible for the red colorobserved in some samples of the treated LMO of the invention.

In a preferred embodiment of this invention, the blends additionallycomprise a basic compound. Such a “basic compound” is any material thatis capable of reacting with and neutralizing acid produced duringoperation of the cell, such as by decomposition of the electrolyte orother battery components as discussed below. A basic compound can beblended in combination with one or more cathode active material, such asthose mentioned above, to provide enhanced performance.

Non-limiting examples of basic compounds include inorganic and organicbases. Examples of inorganic bases include, without limitation,carbonates, metal oxides, hydroxides, phosphates, hydrogen phosphates,dihydrogen phosphates, silicates, aluminates, borates, bicarbonates andmixtures thereof. Preferred basic compounds include the basiccarbonates, basic metal oxides, basic hydroxides, and mixtures thereof.Examples include without limitation LiOH, Li₂O, LiAlO₂, Li₂SiO₃, Li₂CO₃,Na₂CO₃, and CaCO₃. Organic bases useful as the basic compound includebasic amines and other organic bases such as carboxylic acid salts.Examples include without limitation primary, secondary and tertiaryamines, and salts of organic acids such as acetic acid, propanoic acid,butyric acid and the like. Specific examples of amines includen-butylamine, tributylamine, and isopropylamine, as well asalkanolamines. Preferred organic bases include those having 6 carbonatoms or fewer.

In a preferred embodiment, the basic compound is provided in particulateform. In another preferred embodiment, the basic compound is a lithiumcompound. Lithium compounds are preferred because they are morecompatible with other components of the cell which also provide sourcesof lithium ion. Most preferred lithium basic compounds include, but arenot limited to LiOH, Li₂O, LiAlO₂, Li₂SiO₃, and Li₂CO₃.

III. Blends

Various blends of the above-mentioned compounds having the generalformulas A_(a)M_(b)(XY₄)_(c)Z_(d) and A_(e)M_(f)O_(g) are preferred. Thecompounds are preferably mixed with one another to provide an electrodeactive material comprising mixed active particles. In embodimentscomprising a first active material and a second active material, theweight ratio of first material:second material is from about 1:9 toabout 9:1, preferably from about 2:8 to about 8:2. In some embodiments,the weight ratio is from about 3:7 to about 7:3. In some embodiments,the weight ratio is from about 4:6 to about 6:4, preferably about 5:5(i.e., about 1:1).

As will be appreciated by one of skill in the art, varying thecomposition of the active material blend will affect operatingconditions of the battery, such as discharge voltage and cyclingcharacteristics. Thus, a specific blend of active materials can beselected for use within a battery depending on the composition anddesign of the battery and desired performance and operating parameters,such as electrolyte/solvent being used, temperature, voltage profile,etc.

One cathode active material blend is a powder that includes two groupsof particles having differing chemical compositions, wherein each groupof particles comprises a material selected from:

(a) materials of the formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d);

(b) materials of the formula A² _(e)M² _(f)O_(g); and

(c) materials of the formula A³ _(h)Mn_(i)O₄;

wherein

-   -   (i) A¹, A², and A³ are independently selected from the group        consisting of Li, Na, K, and mixtures thereof, and 0<a≦8, 0<e≦6;    -   (ii) M¹ is one or more metals, comprising at least one metal        which is capable of undergoing oxidation to a higher valence        state, and 0.8≦b≦3;    -   (iii) M² is one or more metals, comprising at least one metal        selected from the group consisting of Fe, Co, Ni, Cu, V, Zr, Ti,        and Cr, and 1≦f≦6;    -   (iv) XY₄ is selected from the group consisting of        X′O_(4-x)Y′_(x), O_(4-y)Y′_(2y), X″S₄, and mixtures thereof,        where X′ is selected from the group consisting of P, As, Sb, Si,        Ge, V, S, and mixtures thereof; X″ is selected from the group        consisting of P, As, Sb, Si, Ge, V, and mixtures thereof; Y′ is        halogen; 0≦x<3; and 0<y<2; and 0<c≦3;    -   (v) Z is OH, halogen, or mixtures thereof, and 0≦d≦6;    -   (vi) 0<g≦15;    -   (vii) M¹, M², X, Y, Z, a, b, c, d, e, f, g, h, i, x and y are        selected so as to maintain electroneutrality of said compound;        and    -   (viii) said material of the formula A³ _(h)Mn_(i)O₄ has an inner        and an outer region, wherein the inner region comprises a cubic        spinel manganese oxide, and the outer region comprises a        manganese oxide that is enriched in Mn⁺⁴ relative to the inner        region.

In a preferred embodiment, M¹ and M² comprise two or more transitionmetals from Groups 4 to 11 of the Periodic Table. In another preferredembodiment, M¹ comprises at least one element from Groups 4 to 11 of thePeriodic Table; and at least one element from Groups 2, 3, and 12-16 ofthe Periodic Table. Preferred embodiments include those where c=1, thosewhere c=2, and those where c=3. Preferred embodiments include thosewhere a≦1 and c=1, those where a=2 and c=1, and those where a≧3 and c=3.Preferred embodiments for compounds having the formula A¹ _(a)M¹_(b)(XY₄)_(c)Z_(d) also include those having a structure similar to themineral olivine (herein “olivines”), and those having a structuresimilar to NASICON(NA Super Ionic CONductor) materials (herein“NASICONs”). In another preferred embodiment, M¹ further comprises MO, a+2 ion containing a +4 oxidation state transition metal.

In preferred embodiment, M² comprises at least one transition metal fromGroups 4 to 11 of the Periodic Table, and at least one element fromGroups 2, 3, and 12-16 of the Periodic Table. In another preferredembodiment M² is M⁴ _(k)M⁵ _(m)M⁶ _(n), wherein M⁴ is a transition metalselected from the group consisting of Fe, Co, Ni, Cu, V, Zr, Ti, Cr, andmixtures thereof; M⁵ is one or more transition metal from Groups 4 to 11of the Periodic Table; M⁶ is at least one metal selected from Group 2,12, 13, or 14 of the Periodic Table; and k+m+n=f. Preferred embodimentsof compounds having the formula A² _(e)M² _(f)O_(g) include alkali metaltransition metal oxide and more specifically lithium nickel cobalt metaloxide. In another preferred embodiment A³ _(h)Mn_(i)O₄ has an inner andan outer region, wherein the inner region comprises a cubic spinelmanganese oxide, and the outer region comprises a manganese oxide thatis enriched in Mn⁺⁴ relative to the inner region.

Additional particles can be further added to the mixture of cathodeactive materials to form a terniary blend. The particles can includeadditional active materials as well as compounds selected from a groupof basic compounds. Further blends can be formed by combining four,five, six, etc. compounds together to provide various cathode activematerial blends.

Another combination of cathode active materials includes a powdercomprising two groups of particles having differing chemicalcompositions, wherein

-   -   (a) the first group of particles comprises a material of the        formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d); and    -   (b) the second group of particles comprises a material selected        from materials of the formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d);        materials of the formula A² _(e)M³ _(f)O_(g); and mixtures        thereof;        wherein    -   (i) A¹ and A² are independently selected from the group        consisting of Li, Na, K, and mixtures thereof, and 0<a≦8, and        0<e≦6;    -   (ii) M¹ and M³ are, independently, one or more metals,        comprising at least one metal which is capable of undergoing        oxidation to a higher valence state, and 0.8≦b≦3, and 1≦f≦6;    -   (iii) XY₄ is selected from the group consisting of        X′O_(4-x)Y′_(x), X′O_(4-y)Y′_(2y), X″S₄, and mixtures thereof,        where X′ is selected from the group consisting of P, As, Sb, Si,        Ge, V, S, and mixtures thereof; X″ is selected from the group        consisting of P, As, Sb, Si, Ge, V, and mixtures thereof; Y′ is        halogen; 0≦x<3; and 0<y<2; and 0<c≦3;    -   (iv) Z is OH, halogen, or mixtures thereof, and 0<d≦6;    -   (v) 0<g≦15; and    -   (vi) wherein M¹, M³, X, Y, Z, a, b, c, d, e, f, g, x and y are        selected so as to maintain electroneutrality of said compound.

In a preferred embodiment, M¹ comprises at least one element from Groups4 to 11 of the Periodic Table, and at least one element from Groups 2,3, and 12-16 of the Periodic Table. In another preferred embodiment, M¹comprises MO, a +2 ion containing a +4 oxidation state metal. In anotherpreferred embodiment, M³ is M⁴ _(k)M⁵ _(m)M⁶ _(n), wherein M⁴ is atransition metal selected from the group consisting of Fe, Co, Ni, Cu,V, Zr, Ti, Cr, and mixtures thereof; M⁵ is one or more transition metalfrom Groups 4 to 11 of the Periodic Table; M⁶ is at least one metalselected from Group 2, 12, 13, or 14 of the Periodic Table. In anotherpreferred embodiment A² _(e)M³ _(f)O_(g) comprises a material of theformula A³ _(h)Mn_(i)O₄ having an inner and an outer region, wherein theinner region comprises a cubic spinel manganese oxide, and the outerregion comprises a cubic spinel manganese oxide that is enriched in Mn⁺⁴relative to the inner region. In another preferred embodiment, themixture further comprises a basic compound.

A third cathode active material blend includes two groups of particleshaving differing chemical compositions, wherein

-   -   (a) the first group of particles comprises an inner and an outer        region, wherein the inner region comprises a cubic spinel        manganese oxide, and the outer region comprises a manganese        oxide that is enriched in Mn⁺⁴ relative to the inner region; and    -   (b) the second group of particles comprises a material selected        from materials of the formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d);        materials of the formula A² _(e)M³ _(f)O_(g); and mixtures        thereof;        wherein    -   (i) A¹, A², and A³ are independently selected from the group        consisting of Li, Na, K, and mixtures thereof, and 0<a≦8, 0<e≦6;    -   (ii) M¹ and M³ are, independently, one or more metals,        comprising at least one metal which is capable of undergoing        oxidation to a higher valence state, and 0.8≦b≦3, and 1≦f≦6;    -   (iii) XY₄ is selected from the group consisting of        X′O_(4-x)Y′_(x), X′O_(4-y)Y′C_(2y),

X″S₄, and mixtures thereof, where X′ is selected from the groupconsisting of P, As, Sb, Si, Ge, V, S, and mixtures thereof; X″ isselected from the group consisting of P, As, Sb, Si, Ge, V, and mixturesthereof; Y′ is halogen; 0≦x<3; and 0<y<2; and 0<c≦3;

-   -   (iv) Z is OH, halogen, or mixtures thereof, and 0≦d≦6;    -   (v) 0<g≦15; and    -   (vi) wherein M¹, M³, X, Y, Z, a, b, c, d, e, f, g, x and y are        selected so as to maintain electroneutrality of said compound.

A terniary blend of cathode active materials includes three groups ofparticles having differing chemical compositions, wherein each group ofparticles comprises a material selected from

(a) materials of the formula A¹ _(a)NI¹ _(b)(XY₄)_(c)Z_(d);

(b) materials of the formula A² _(e)M³ _(f)O_(g); and mixtures thereof;wherein

-   -   (i) A¹ and A² are independently selected from the group        consisting of Li, Na, K, and mixtures thereof, and 0<a≦8, and        0<e≦6;    -   (ii) M¹ and M³ independently comprise one or more metals,        comprising at least one metal which is capable of undergoing        oxidation to a higher valence state, and 0.8≦b≦3, and 1≦f≦6;    -   (iii) XY₄ is selected from the group consisting of        X′O_(4-x),Y′_(x), X′O_(4-y)Y′_(2y), X″S₄, and mixtures thereof,        where X′ is selected from the group consisting of P, As, Sb, Si,        Ge, V, S, and mixtures thereof; X″ is selected from the group        consisting of P, As, Sb, Si, Ge, V, and mixtures thereof; Y′ is        halogen; 0≦x<3; and 0<y<2; and 0<c≦3;    -   (iv) Z is OH, halogen, or mixtures thereof, and 0≦d≦6;    -   (v) 0<g≦15; and    -   (vi) wherein M¹, M³, X, Y, Z, a, b, c, d, e, f, g, x and y are        selected so as to maintain electroneutrality of said compound.

One embodiment comprises: (a) a first material having the generalformula A_(a)M_(b)(XY₄)_(c)Z_(d), where A is L₁, XY₄ is PO₄, and c is 1;with (b) a second material of the formula A_(e)M_(f)O_(g). In apreferred embodiment, the first material is LiFe_(1-q)Mg_(q),PO₄ where0<q<0.5. Preferred first materials are selected from the groupconsisting of LiFe_(0.9) mg_(0.1)PO₄; LiFeo_(0.8)Mg_(0.2)PO₄;LiFe_(0.95)Mg_(0.05)PO₄; and mixtures thereof. Preferably the secondmaterial is selected from the group consisting ofLiNi_(0.8)Co_(0.15)Al_(0.05)O₂; LiNiO₂; LiCoO₂; γ-LiV₂O₅; LiMnO₂;LiMoO₂; Li₂CuO₂; LiNi_(r)Co_(s)M_(t)O₂; LiMn₂O₄, modified manganeseoxide material of formula LiMn_(i)O₄, and mixtures thereof. In apreferred embodiment, the second material is selected from the groupconsisting of LiNi_(0.8)Co_(0.15)Al_(0.05)O₂; LiNiO₂; LiCoO₂; γ-LiV₂O₅;and mixtures thereof. Preferably such preferred blends comprise fromabout 50% to about 80% (by weight) of the first material, morepreferably from about 60% to about 70% of the first material.

Another embodiment of the present invention the active material blendcomprises two or more groups of particles having differing chemicalcompositions, wherein each group of particles comprises a materialselected from:

(a) materials of the formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d); and

(b) materials of the formula LiMn₂O₄ or Li_(i),Mn_(2-z)O;

wherein

-   -   (i) A¹ is selected from the group consisting of Li, Na, K, and        mixtures thereof, and 0<a≦8;    -   (ii) M¹ is one or more metals, comprising at least one metal        which is capable of undergoing oxidation to a higher valence        state, and 0.8≦b≦3;    -   (iii) XY₄ is selected from the group consisting of        X′O_(4-x),Y′_(x), X′O_(4-y)Y′_(2y), X″S₄, and mixtures thereof,        where X′ is selected from the group consisting of P, As, Sb, Si,        Ge, V, S, and mixtures thereof; X″ is selected from the group        consisting of P, As, Sb, Si, Ge, V and mixtures thereof; Y′ is        halogen; 0≦x<3; and 0<y<2; and 0<c≦3;    -   (v) Z is OH, halogen, or mixtures thereof, and 0≦d≦6; and        -   (vi) M¹, X, Y, Z, a, b, c, d, x, y and z are selected so as            to maintain electroneutrality of said compound.

The LiMn₂O₄ or Li_(i),Mn_(2-z)O₄ useful in this embodiment can be“treated” as known to those skilled in the art. The “treated” lithiummanganese oxide are “treated” with a basic material that will react withacids in a battery configuration, which acids would otherwise react withthe lithium manganese oxide. For example, the LiMn₂O₄ orLi_(1+z)Mn_(2-z)O₄ can be coated with Li₂MnO₃ or Na₂MnO₃ as disclosed inU.S. Patent Application 20020070374-A1 published on Jun. 13, 2002.Another manner of “treating” the LiMn₂O₄ or Li_(i),Mn_(2-z)O₄ is tosimply mix it with a basic compound that will neutralize the acids in abattery that would react with the lithium manganese oxide as disclosedin U.S. Pat. No. 6,183,718 issued on Feb. 6, 2001. JP 7262984 toYamamoto discloses LiMn₂O₄ coated with Li₂MnO₃ wherein the complex isformed by the decomposition product of LiMn₂O₄ in the presence of LiOH.Another example of treated lithium manganese oxide is described in U.S.6,322,744 issued Nov. 27, 2001 wherein a cationic metal species is boundto the spinel at anionic sites of the lithium manganese particlesurface. Another example of a “treated” lithium manganese oxide is acomposition comprising lithium-enriched manganese oxide represented bythe general formula Li_(1+z)Mn_(2-z)O₄ wherein 0.08<z≦0.20, which is thedecomposition product of a (a) spinel lithium manganese oxide of thegeneral formula Li_(1+x)Mn_(2-x)O₄ wherein 0<x≦0.20, in the presence of(b) lithium carbonate wherein x<z. (See U.S. Pat. No. 6,183,718 issuedFeb. 6, 2001.)

Another embodiment comprises (a) a first material selected from thegroup consisting of LiF_(0.9)Mg_(0.1)PO₄; LiFe_(0.8)Mg_(0.8)PO₄;LiFe_(0.95) Mg_(0.05)PO₄; and mixtures thereof; and (b) a secondmaterial having the formula LiNi_(r)Co_(s)M_(t)O₂, wherein 0<(r+s)≦1,and 0≦t<1. Preferably M is at least one metal selected from Group 2, 12,13, or 14 of the Periodic Table. More preferably M is selected from thegroup consisting of Mg, Ca, Al, and mixtures thereof. Preferably, thesecond material is selected from the group consisting ofLiNi_(0.8)Co_(0.15)Al_(0.05)O₂, LiNi_(0.6)Co_(0.2)Al_(0.2)O₂,LiNi_(0.8)Co_(0.15)Mg_(0.05)O₂, LiNi_(0.8)Co_(0.15)Ca_(0.05)O₂,NaNi_(0.8)Co_(0.15)Al_(0.05)O₂, and mixtures thereof. Preferably suchblends comprise from about 50% to about 80% (by weight) of the firstmaterial, more preferably from about 60% to about 70% of the firstmaterial.

In another embodiment, the blends of this invention comprise (a) a firstmaterial having the general formula A_(a)M_(b)(XY₄)_(c)Z_(d), preferablywhere A is Li, XY₄ is PO₄, and c is 1; (b) a second material of theformula A_(e)M_(f)O_(g); and (c) a basic compound, preferably Li₂CO₃. Ina preferred embodiment, the first material is LiFe_(0.9)Mg_(0.1)PO₄;LiFe_(0.8)Mg_(0.2)PO₄; LiFe_(0.95)Mg_(0.05)PO₄; LiCu_(0.8)Fe_(0.1)Al_(0.025) Mg_(0.05)PO_(3.975)F_(0.025); and mixtures thereof; thesecond material is LiMn₂O₄; and the basic compound is Li₂CO₃. In anotherpreferred embodiment, the second material is a modified manganese oxidematerial of formula LiMn_(i)O₄. Preferably such preferred blendscomprise from about 50% to about 80% (by weight) of the first material,more preferably from about 60% to about 70% of the first material.

Another embodiment comprises: (a) a first material having the generalformula Li_(a)Co_(u)Fe_(v)M¹³ _(w)M¹⁴ _(aa)M¹⁵ _(bb)XY₄; and (b) asecond material of the formula A_(e)M_(f)O_(g). In a preferredembodiment, the first material isLiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025). Preferably thesecond material is selected from the group consisting ofLiNi_(0.8)Co_(0.15)Al_(0.05)O₂; LiNiO₂; LiCoO₂; γ-LiV₂O₅; LiMnO₂;LiMoO₂; Li₂CuO₂; LiNi_(r)Co_(s)M_(t)O₂; LiMn₂O₄, modified manganeseoxide material of formula LiMn_(i)O₄, and mixtures thereof. In apreferred embodiment, the second material is selected from the groupconsisting of LiNi_(0.8)Co_(0.15)Al_(0.05)O₂; LiNiO₂; LiCoO₂; γ-LiV₂O₅;and mixtures thereof. Preferably such preferred blends comprise fromabout 50% to about 80% (by weight) of the first material, morepreferably from about 60% to about 70% of the first material.

Another embodiment comprises (a) a first material having the generalformula Li_(a)Co_(u)Fe_(v)M¹³ _(w)M¹⁴ _(aa)M¹⁵ _(bb)XY₄; and (b) asecond material having the formula LiNi_(r)Co_(s)M_(t)O₂ wherein0<(r+s)≦1, and 0≦t<1. Preferably M is at least one metal selected fromGroup 2, 12, 13, or 14 of the Periodic Table. More preferably M isselected from the group consisting of Mg, Ca, Al, and mixtures thereof.Preferably, the second material is selected from the group consisting ofLiNi_(0.8)Co_(0.15)Al_(0.05)O₂, LiNi_(0.6)Co_(0.2)Al_(0.2)O₂,LiNi_(0.8)Co_(0.15)Mg_(0.05)O₂, LiNi_(0.8)Co_(0.15)Ca_(0.05)O₂,NaNi_(0.8)Co_(0.15)Al_(0.05)O₂, and mixtures thereof. Preferably suchpreferred blends comprise from about 50% to about 80% (by weight) of thefirst material, more preferably from about 60% to about 70% of the firstmaterial.

Another embodiment comprises: (a) a first material having the generalformula Li_(a)M¹¹ _(b)(PO₄)Z_(d), where 0<d≦4, and Z is preferably F;and (b) a second material of the formula A_(e)M_(f)O_(g). Preferably thesecond material is selected from the group consisting ofLiNi_(0.8)Co_(0.15)Al_(0.05)O₂; LiNiO₂; LiCoO₂; γ-LiV₂O₅; LiMnO₂;LiMoO₂; Li₂CuO₂; LiNi_(r)Co_(s)M_(t)O₂; LiMn₂O₄, modified manganeseoxide material of formula LiMn_(i)O₄, and mixtures thereof. In apreferred embodiment, the second material is selected from the groupconsisting of LiNi_(0.8)Co_(0.15)Al_(0.05)O₂; LiNiO₂; LiCoO₂; γ-LiV₂O₅;and mixtures thereof. Preferably such preferred blends comprise fromabout 50% to about 80% (by weight) of the first material, morepreferably from about 60% to about 70% of the first material.

Another embodiment comprises (a) a first material having the generalformula Li_(a)M¹¹ _(b)(PO₄)Z_(d), where 0<d≦4, and Z is preferably F;and (b) a second material having the formula LiNi, Co_(s)M_(t)O₂ wherein0<(r+s)≦1, and 0≦t<1. Preferably M is at least one metal selected fromGroup 2, 12, 13, or 14 of the Periodic Table. More preferably M isselected from the group consisting of Mg, Ca, Al, and mixtures thereof.Preferably, the second material is selected from the group consisting ofLiNi_(0.8)Co_(0.15)Al_(0.05)O₂, LiNi_(0.6)Co_(0.2)Al_(0.2)O₂,LiNi_(0.8)Co_(0.15)Mg_(0.05)O₂, LiNi_(0.8)Co_(0.15)Ca_(0.05)O₂,NaNi_(0.8)Co_(0.15)Al_(0.05)O₂, and mixtures thereof. Preferably suchpreferred blends comprise from about 50% to about 80% (by weight) of thefirst material, more preferably from about 60% to about 70% of the firstmaterial.

Another embodiment comprises: (a) a first material having the generalformula A_(a)M_(b)(XY₄)_(c)Z_(d), where A is L₁, XY₄ is PO₄, and c is 1,with (b) a second material of the formula A_(a)M_(b)(XY₄)_(c)Z_(d). In apreferred embodiment, the first material is LiFe_(1-q)Mg_(q)PO₄ where0<q<0.5, preferably selected from the group consisting ofLiFe_(0.9)Mg_(0.1)PO₄; LiFe_(0.8)Mg_(0.2)PO₄; LiFe_(0.95)Mg_(0.05)PO₄;and mixtures thereof. In another preferred embodiment, the firstmaterial is of the formula Li_(a)Co_(u)Fe_(v)M¹³ _(w)M¹⁴ _(aa)M¹⁵_(bb)XY₄; preferablyLiCu_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025). Preferredsecond materials include those selected from the group consisting ofLiFePO₄; LiFe_(0.9)Mg_(0.1)PO₄; LiFe_(0.8)Mg_(0.2)PO₄;LiCo_(0.9)Mg_(0.1)PO₄,Li_(1.025)Co_(0.85)Fe_(0.05)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.7)Fe_(0.10)A_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.75)Fe_(0.15)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.7)(Fe_(0.4)Mn_(0.6))_(0.2)Al_(0.025)Mg_(0.05)PO₄,LiCo_(0.8)Fe_(0.1)Al_(0.025)Ca_(0.05)PO_(3.975)F_(0.025),LiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025),LiCo_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.05)PO₄;Li_(1.025)Co_(0.8)Fe_(0.1)Ti_(0.025)Al_(0.025)PO₄;Li_(1.025)Co_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.025)PO_(3.975)F_(0.025);LiCo_(0.825)Fe_(0.1)Ti_(0.025)Mg_(0.025)PO₄;LiCo_(0.85)Fe_(0.075)Ti_(0.025)Mg_(0.025)PO₄;LiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025) and mixturesthereof. Preferably such preferred blends comprise from about 50% toabout 80% (by weight) of the first material, more preferably from about60% to about 70% of the first material. In some embodiments, such blendsadditionally comprise a basic compound, preferably Li₂CO₃.

Another embodiment comprises: (a) a first material having the generalformula A_(a)M_(b)(XY₄)_(c)Z_(d), having an olivine structure where A isLi, a is about 1, XY₄ is PO₄, and c is 1, with (b) a second material ofthe formula A_(a)M_(b)(XY₄)_(c) having a NASICON structure, where A isL₁, XY₄ is PO₄, and c is 3. In a preferred embodiment, the firstmaterial is LiFe_(1-q)Mg_(q)PO₄ where 0<q<0.5, preferably selected fromthe group consisting of LiFe_(0.9)Mg_(0.1)PO₄; LiFe_(0.8)Mg_(0.2)PO₄;LiFe_(0.95)Mg_(0.05)PO₄; and mixtures thereof. In another preferredembodiment, the first material is of the formula Li_(a)Co_(u)Fe_(v)M¹³_(w)M¹⁴ _(aa)M¹⁵ _(bb)XY₄; preferably LiCo_(0.8)Fe_(0.1) Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025). Preferred second material include thoseselected from the group consisting of Li₃V₂(PO₄)₃; Li₃Fe₂(PO₄)₃;Li₃Mn₂(PO₄)₃; Li₃FeTi(PO₄)₃; Li₃CoMn(PO₄)₃; Li₃FeV(PO₄)₃; Li₃VTi(PO₄)₃;Li₃FeCr(PO₄)₃; Li₃FeMo(PO₄)₃; Li₃FeNi(PO₄)₃; Li₃FeMn(PO₄)₃;Li₃FeAl(PO₄)₃; Li₃FeCo(PO₄)₃; Li₃Ti₂(PO₄)₃; Li₃TiCr(PO₄)₃;Li₃TiMn(PO₄)₃; Li₃TiMo(PO₄)₃; Li₃TiCo(PO₄)₃; Li₃TiAl(PO₄)₃;Li₃TiNi(PO₄)₃; and mixtures thereof. Preferably such preferred blendscomprise from about 50% to about 80% (by weight) of the first material,more preferably from about 60% to about 70% of the first material. Insome embodiments, such blends additionally comprise a basic compound,preferably Li₂CO₃,

Another embodiment comprises: (a) a first material of the formulaA_(a)M_(b)(XY₄)_(c)Z_(d) having the having a NASICON structure, where Ais L₁, XY₄ is PO₄, and c is 3; and a second material a second materialof the formula A_(e)M_(f)O_(g). Preferably, the first material isselected from the group consisting of Li₃V₂(PO₄)₃; Li₃Fe₂(PO₄)₃;Li₃Mn₂(PO₄)₃; Li₃FeTi(PO₄)₃; Li₃CoMn(PO₄)₃; Li₃FeV(PO₄)₃; Li₃VTi(PO₄)₃;Li₃FeCr(PO₄)₃; Li₃FeMo(PO₄)₃; Li₃FeNi(PO₄)₃; Li₃FeMn(PO₄)₃;Li₃FeAl(PO₄)₃; Li₃FeCo(PO₄)₃; Li₃Ti₂(PO₄)₃; Li₃TiCr(PO₄)₃;Li₃TiMn(PO₄)₃; Li₃TiMo(PO₄)₃; Li₃TiCo(PO₄)₃; Li₃TiAl(PO₄)₃;Li₃TiNi(PO₄)₃; and mixtures thereof. Preferably the second material isselected from the group consisting of LiNi_(0.8)Co_(0.15)Al_(0.05)O₂;LiNiO₂; LiCoO₂; γ-LiV₂O₅; LiMnO₂; LiMoO₂; Li₂CuO₂;LiNi_(r)Co_(s)M_(t)O₂; LiMn₂O₄, modified manganese oxide material offormula LiMn_(i)O₄, and mixtures thereof. In a preferred embodiment, thesecond material is selected from the group consisting ofLiNi_(0.8)Co_(0.15)Al_(0.05)O₂; LiNiO₂; LiCoO₂; γ-LiV₂O₅; and mixturesthereof. Preferably such preferred blends comprise from about 50% toabout 80% (by weight) of the first material, more preferably from about60% to about 70% of the first material. In some embodiments, such blendsadditionally comprise a basic compound, preferably Li₂CO₃.

Another embodiment comprises: (a) a first material of the formulaA_(a)M_(b)(XY₄)_(c)Z_(d) having a NASICON structure, where A is L₁, XY₄is PO₄, and c is 3; and a second material a second material of theformula LiNi_(r)Co_(s)M_(t)O₂ wherein 0<(r+s)≦1, and 0≦t<1, preferably Mis at least one metal selected from Group 2, 12, 13, or 14 of thePeriodic Table, more preferably M is selected from the group consistingof Mg, Ca, Al, and mixtures thereof. Preferably, the first material isselected from the group consisting of Li₃V₂(PO₄)₃; Li₃Fe₂(PO₄)₃;Li₃Mn₂(PO₄)₃; Li₃FeTi(PO₄)₃; Li₃CoMn(PO₄)₃;Li₃FeV(PO₄)₃; Li₃VTi(PO₄)₃;Li₃FeCr(PO₄)₃; Li₃FeMo(PO₄)₃; Li₃FeNi(PO₄)₃; Li₃FeMn(PO₄)₃;Li₃FeAl(PO₄)₃; Li₃FeCo(PO₄)₃; Li₃Ti₂(PO₄)₃; Li₃TiCr(PO₄)₃;Li₃TiMn(PO₄)₃; Li₃TiMo(PO₄)₃; Li₃TiCo(PO₄)₃; Li₃TiAl(PO₄)₃;Li₃TiNi(PO₄)₃; and mixtures thereof. Preferably, the second material isselected from the group consisting of LiNi_(0.8)Co_(0.15)Al_(0.05)O₂,LiNi_(0.6)Co_(0.2)Al_(0.2)O₂, LiNi_(0.8)Co_(0.15)Mg_(0.05)O₂,LiNi_(0.8)Co_(0.15)Ca_(0.05)O₂, NaNi_(0.8)Co_(0.15)Al_(0.05)O₂, andmixtures thereof. In some embodiments, such blends additionally comprisea basic compound, preferably Li₂CO₃. Preferably such preferred blendscomprise from about 50% to about 80% (by weight) of the first material,more preferably from about 60% to about 70% of the first material. Insome embodiments, such blends additionally comprise a basic compound,preferably Li₂CO₃.

Another embodiment comprises (a) as a first material, a modifiedmanganese oxide material of formula LiMn_(i)O₄; and (b) a secondmaterial of the formula A_(a)M_(b)(XY₄)_(c)Z_(d). In a preferredembodiment, the second material is LiFe_(1-q)Mg_(q)PO₄ where 0<q<0.5,preferably selected from the group consisting of LiFe_(0.9)Mg_(0.1)PO₄;LiFe_(0.8)Mg_(0.2)PO₄; LiFe_(0.95)Mg_(0.05)PO₄; and mixtures thereof. Inanother preferred embodiment, the second material is of the formulaLi_(a)Co_(u)Fe_(v)M¹³ _(w)M¹⁴ _(aa)M¹⁵ _(bb)XY₄; preferablyLiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025). Preferredsecond materials include those selected from the group consisting ofLiFePO₄, LiFe_(0.9)Mg_(0.1)PO₄, LiFe_(0.8)Mg_(0.2)PO₄,LiFe_(0.95)Mg_(0.05)PO₄, LiCo_(0.9)Mg_(0.1)PO₄,Li_(1.025)Co_(0.85)Fe_(0.05)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.80)Fe_(0.10)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.75)Fe_(0.15)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.7)(Fe_(0.4)Mn_(0.6))_(0.2)Al_(0.025)Mg_(0.05)PO₄,LiCo_(0.8)Fe_(0.1)Al_(0.025)Ca_(0.05)PO_(3.975)F_(0.025),LiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025),LiCo_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.05)PO₄;Li_(1.025)Co_(0.8)Fe_(0.1)Ti_(0.025)Al_(0.025)PO₄;Li_(1.025)Co_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.025)PO_(3.975)F_(0.025);LiCo_(0.825)Fe_(0.1)Ti_(0.025)Mg_(0.025)PO₄;LiCo_(0.85)Fe_(0.075)Ti_(0.025)Mg_(0.025)PO₄;LiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025) and mixturesthereof. Preferably such preferred blends comprise from about 50% toabout 80% (by weight) of the first material, more preferably from about60% to about 70% of the first material. In some embodiments, such blendsadditionally comprise a basic compound, preferably Li₂CO₃.

Another embodiment comprises (a) as a first material, a modifiedmanganese oxide material of formula LiMn_(i)O₄; and (b) a secondmaterial of the formula A_(e)M_(f)O_(g). Preferably the second materialis selected from the group consisting of LiNi_(0.8)Co_(0.15)Al_(0.05)O₂;LiNiO₂; LiCoO₂; γ-LiV₂O₅; LiMnO₂; LiMoO₂; Li₂CuO₂; and mixtures thereof.Preferably such preferred blends comprise from about 50% to about 80%(by weight) of the first material, more preferably from about 60% toabout 70% of the first material. In some embodiments, such blendsadditionally comprise a basic compound, preferably Li₂CO₃.

Another embodiment comprises (a) as a first material, an oxide materialof formula A_(e)M_(f)O_(g); and (b) a second material of the formulaA_(e)M_(f)O_(g).

Preferably the second material is selected from the group consisting ofLiNi_(0.8)Co_(0.15)Al_(0.05)O₂; LiNiO₂; LiCoO₂; γ-LiV₂O₅; LiMnO₂;LiMoO₂; Li₂CuO₂; and mixtures thereof. If the first material is LiMn₂O₄,then the second material is not LiNiO₂; LiCoO₂, LiNi_(r)Co_(s)O₂ orLi₂CuO₂. Preferably such preferred blends comprise from about 50% toabout 80% (by weight) of the first material, more preferably from about60% to about 70% of the first material. In some embodiments, such blendsadditionally comprise a basic compound, preferably Li₂CO₃.

Another embodiment comprises: (a) a first material having the generalformula A_(a)M_(b)(XY₄)_(c)Z_(d), having a NASICON structure where A isLi, a is about 3, XY₄ is PO₄, and c is 3, with (b) a second material ofthe formula A_(a)M_(b)(XY₄)_(c)Z_(d). Preferably, the first material isselected from the group consisting of Li₃V₂(PO₄)₃; Li₃Fe₂(PO₄)₃;Li₃Mn₂(PO₄)₃; Li₃FeTi(PO₄)₃; Li₃COMn(PO₄)₃; Li₃FeV(PO₄)₃; Li₃VTi(PO₄)₃;Li₃FeCr(PO₄)₃; Li₃FeMo(PO₄)₃; Li₃FeNi(PO₄)₃; Li₃FeMn(PO₄)₃;Li₃FeAl(PO₄)₃; Li₃FeCo(PO₄)₃; Li₃Ti₂(PO₄)₃; Li₃TiCr(PO₄)₃;Li₃TiMn(PO₄)₃; Li₃TiMo(PO₄)₃; Li₃TiCo(PO₄)₃; Li₃TiAl(PO₄)₃;Li₃TiNi(PO₄)₃; and mixtures thereof. In a preferred embodiment, thesecond material is selected from the group consisting of Li₃V₂(PO₄)₃;Li₃Fe₂(PO₄)₃; Li₃Mn₂(PO₄)₃; Li₃FeTi(PO₄)₃; Li₃CoMn(PO₄)₃; Li₃FeV(PO₄)₃;Li₃VTi(PO₄)₃; Li₃FeCr(PO₄)₃; Li₃FeMo(PO₄)₃; Li₃FeNi(PO₄)₃;Li₃FeMn(PO₄)₃; Li₃FeAl(PO₄)₃; Li₃FeCo(PO₄)₃; Li₃Ti₂(PO₄)₃;Li₃TiCr(PO₄)₃; Li₃TiMn(PO₄)₃; Li₃TiMo(PO₄)₃; Li₃TiCo(PO₄)₃;Li₃TiAl(PO₄)₃; Li₃TiNi(PO₄)₃; and mixtures thereof. In another preferredembodiment, the second material is LiFe_(1-q)Mg_(q)PO₄ where 0<q<0.5,preferably selected from the group consisting of LiFe_(0.9)Mg_(0.1)PO₄;LiFe_(0.8)Mg_(0.2)PO₄; LiFe_(0.95)Mg_(0.05)PO₄; and mixtures thereof. Inanother preferred embodiment, the second material is of the formulaLi_(a)Co_(u)Fe_(v)M¹³ _(w)M¹⁴ _(aa)M¹⁵ _(bb)XY₄; preferablyLiCu_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025). Preferredsecond materials include those selected from the group consisting ofLiFePO₄; LiFe_(0.9)Mg_(0.1)PO₄; LiFe_(0.8)Mg_(0.2)PO₄;LiCo_(0.9)Mg_(0.1)PO₄,Li_(1.025)Co_(0.85)Fe_(0.05)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.80)Fe_(0.10)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.75)Fe_(0.15)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.7)(Fe_(0.4)Mn_(0.6))_(0.2)Al_(0.025)Mg_(0.05)PO₄,LiCo_(0.8)Fe_(0.1)Al_(0.025)Ca_(0.05)PO_(3.975)F_(0.025),LiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025),LiCo_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.05)PO₄;Li_(1.025)Co_(0.8)Fe_(0.1)Ti_(0.025)Al_(0.025)PO₄;Li_(1.025)Co_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.025)PO_(3.975)F_(0.025);LiCo_(0.825)Fe_(0.1)Ti_(0.025)Mg_(0.025)PO₄;LiCo_(0.85)Fe_(0.075)Ti_(0.025)Mg_(0.025)PO₄;LiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025) and mixturesthereof. Preferably such preferred blends comprise from about 50% toabout 80% (by weight) of the first material, more preferably from about60% to about 70% of the first material.

More specifically, a preferred embodiment includes (a) a first activematerial of the formula LiFe_(0.95)Mg_(0.05)PO₄ with (b) a second activematerial selected from the group consisting of LiNiO₂, LiCoO₂,LiNi_(x)Co_(1-x)O₂ where 0<x<1, Li₃V₂(PO₄)₃, Li_(3+x)Ni₂(PO₄)₃ where0<x<2, Li_(3+x)Cu₂(PO₄)₃ where 0<x<2; Li_(3+x)Co₂(PO₄)₃ where 0<x<2,Li₃,Mn₂(PO₄)₃ where 0<x<2, γ-LiV₂O₅, LiMn₂O₄, Li₂CuO₂, LiFePO₄, LiMnPO₄,LiFe_(x)Mn_(1-x)PO₄ where 0<x<1; LiVPO₄F and Li_(1-x)VPO₄F where 0<x<1.

Another preferred embodiment includes (a) a first active material of theformula LiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025) and (b)a second active material selected from the group consisting of LiNiO₂,LiCoO₂, LiNi_(x)Co_(1-x)O₂ where 0<x<1, Li₃V₂(PO₄)₃, Li_(3+x)V₂(PO₄)₃where 0<x<2, LiNiPO₄, LiCoPO₄, LiNi_(x)Co_(1-x)PO₄ where 0<x<1, andLi_(1-x)VPO₄F where 0≦x<1.

Methods of Manufacturing A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d):

Active materials of general formula A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d) arereadily synthesized by reacting starting materials in a solid statereaction, with or without simultaneous oxidation or reduction of themetal species involved. According to the desired values of a, b, c, andd in the product, starting materials are chosen that contain “a” molesof alkali metal A¹ from all sources, “b” moles of metals M¹ from allsources, “c” moles of phosphate (or other XY₄ species) from all sources,and “d” moles of halide or hydroxide Z, again taking into account allsources. As discussed below, a particular starting material may be thesource of more than one of the components A¹, M¹, XY₄, or Z.Alternatively it is possible to run the reaction with an excess of oneor more of the starting materials. In such a case, the stoichiometry ofthe product will be determined by the limiting reagent among thecomponents A¹, M¹, XY₄, and Z. Because in such a case at least some ofthe starting materials will be present in the reaction product mixture,it is usually desirable to provide exact molar amounts of all thestarting materials.

In one aspect, the moiety XY₄ of the active material comprises asubstituted group represented by X′O_(4-x)Y′_(x), where x is less thanor equal to 1, and preferably less than or equal to about 0.1. Suchgroups may be synthesized by providing starting materials containing, inaddition to the alkali metal and other metals, phosphate or other X′O₄material in a molar amount equivalent to the amount necessary to producea reaction product containing X′O₄. Where Y′ is F, the startingmaterials further comprise a source of fluoride in a molar amountsufficient to substitute F in the product as shown in the formula. Thisis generally accomplished by including at least “x” moles of F in thestarting materials. For embodiments where d>0, the fluoride source isused in a molar limiting quantity such that the fluorine is incorporatedas a Z-moiety. Sources of F include ionic compounds containing fluorideion (F⁻) or hydrogen difluoride ion (HF₂ ⁻). The cation may be anycation that forms a stable compound with the fluoride or hydrogendifluoride anion. Examples include +1, +2, and +3 metal cations, as wellas ammonium and other nitrogen-containing cations. Ammonium is apreferred cation because it tends to form volatile by-products that arereadily removed from the reaction mixture.

Similarly, to make X′O_(4-x)N_(x), starting materials are provided thatcontain “x” moles of a source of nitride ion. Sources of nitride areamong those known in the art including nitride salts such as Li₃N and(NH₄)₃N.

It is preferred to synthesize the active materials of the inventionusing stoichiometric amounts of the starting materials, based on thedesired composition of the reaction product expressed by the subscriptsa, b, c, and d above. Alternatively it is possible to run the reactionwith a stoichiometric excess of one or more of the starting materials.In such a case, the stoichiometry of the product will be determined bythe limiting reagent among the components. There will also be at leastsome unreacted starting material in the reaction product mixture.Because such impurities in the active materials are generallyundesirable (with the exception of reducing carbon, discussed below), itis generally preferred to provide relatively exact molar amounts of allthe starting materials.

The sources of components A¹, M¹, phosphate (or other XY₄ moiety) andoptional sources of F or N discussed above, and optional sources of Zmay be reacted together in the solid state while heating for a time andat a temperature sufficient to make a reaction product. The startingmaterials are provided in powder or particulate form. The powders aremixed together with any of a variety of procedures, such as by ballmilling, blending in a mortar and pestle, and the like. Thereafter themixture of powdered starting materials may be compressed into a pelletand/or held together with a binder material to form a closely coheringreaction mixture. The reaction mixture is heated in an oven, generallyat a temperature of about 400° C. or greater until a reaction productforms.

Another means for carrying out the reaction at a lower temperature is ahydrothermal method. In a hydrothermal reaction, the starting materialsare mixed with a small amount of a liquid such as water, and placed in apressurized bomb. The reaction temperature is limited to that which canbe achieved by heating the liquid water under pressure, and theparticular reaction vessel used.

The reaction may be carried out without redox, or if desired, underreducing or oxidizing conditions. When the reaction is carried out underreducing conditions, at least some of the transition metals in thestarting materials are reduced in oxidation state. When the reaction isdone without redox, the oxidation state of the metal or mixed metals inthe reaction product is the same as in the starting materials. Oxidizingconditions may be provided by running the reaction in air. Thus, oxygenfrom the air is used to oxidize the starting material containing thetransition metal.

The reaction may also be carried out with reduction. For example, thereaction may be carried out in a reducing atmosphere such as hydrogen,ammonia, methane, or a mixture of reducing gases. Alternatively, thereduction may be carried out in situ by including in the reactionmixture a reductant that will participate in the reaction to reduce ametal M, but that will produce by-products that will not interfere withthe active material when used later in an electrode or anelectrochemical cell. The reductant is described in greater detailbelow.

Sources of alkali metal include any of a number of salts or ioniccompounds of lithium, sodium, potassium, rubidium or cesium. Lithium,sodium, and potassium compounds are preferred. Preferably, the alkalimetal source is provided in powder or particulate form. A wide range ofsuch materials is well known in the field of inorganic chemistry.Non-limiting examples include the lithium, sodium, and/or potassiumfluorides, chlorides, bromides, iodides, nitrates, nitrites, sulfates,hydrogen sulfates, sulfites, bisulfites, carbonates, bicarbonates,borates, phosphates, hydrogen ammonium phosphates, dihydrogen ammoniumphosphates, silicates, antimonates, arsenates, germinates, oxides,acetates, oxalates, and the like. Hydrates of the above compounds mayalso be used, as well as mixtures. In particular, the mixtures maycontain more than one alkali metal so that a mixed alkali metal activematerial will be produced in the reaction.

Sources of metals M¹ include salts or compounds of any of the transitionmetals, alkaline earth metals, or lanthanide metals, as well as ofnon-transition metals such as aluminum, gallium, indium, thallium, tin,lead, and bismuth. The metal salts or compounds include, withoutlimitation, fluorides, chlorides, bromides, iodides, nitrates, nitrites,sulfates, hydrogen sulfates, sulfites, bisulfites, carbonates,bicarbonates, borates, phosphates, hydrogen ammonium phosphates,dihydrogen ammonium phosphates, silicates, antimonates, arsenates,germanates, oxides, hydroxides, acetates, oxalates, and the like.Hydrates may also be used, as well as mixtures of metals, as with thealkali metals, so that alkali metal mixed metal active materials areproduced. The metal M in the starting material may have any oxidationstate, depending the oxidation state required in the desired product andthe oxidizing or reducing conditions contemplated, as discussed below.The metal sources are chosen so that at least one metal in the finalreaction product is capable of being in an oxidation state higher thanit is in the reaction product. In a preferred embodiment, the metalsources also include a +2 non-transition metal. Also preferably, atleast one metal source is a source of a +3 non-transition metal. Inembodiments comprising Ti, a source of Ti is provided in the startingmaterials and the compounds are made using reducing or non-reducingconditions depending on the other components of the product and thedesired oxidation state of Ti and other metals in the final product.Suitable Ti-containing precursors include TiO₂, Ti₂O₃, and TiO.

Sources of the desired starting material anions such as the phosphates,halides, and hydroxides are provided by a number of salts or compoundscontaining positively charged cations in addition to the source ofphosphate (or other XY₄ species), halide, or hydroxide. Such cationsinclude, without limitation, metal ions such as the alkali metals,alkaline metals, transition metals, or other non-transition metals, aswell as complex cations such as ammonium or quaternary ammonium. Thephosphate anion in such compounds may be phosphate, hydrogen ammoniumphosphate, or dihydrogen ammonium phosphate. As with the alkali metalsource and metal source discussed above, the phosphate, halide, orhydroxide starting materials are preferably provided in particulate orpowder form. Hydrates of any of the above may be used, as can mixturesof the above.

A starting material may provide more than one of the components A¹, M¹,XY₄, and Z, as is evident in the list above. In various embodiments ofthe invention, starting materials are provided that combine, forexample, the alkali metal and halide together, or the metal and thephosphate. Thus for example, lithium, sodium, or potassium fluoride maybe reacted with a metal phosphate such as vanadium phosphate or chromiumphosphate, or with a mixture of metal compounds such as a metalphosphate and a metal hydroxide. In one embodiment, a starting materialis provided that contains alkali metal, metal, and phosphate. There iscomplete flexibility to select starting materials containing any of thecomponents of alkali metal A¹, metal M¹, phosphate (or other XY₄moiety), and halide/hydroxide Z, depending on availability. Combinationsof starting materials providing each of the components may also be used.

In general, any anion may be combined with the alkali metal cation toprovide the alkali metal source starting material, or with the metal Mcation to provide the metal M starting material. Likewise, any cationmay be combined with the halide or hydroxide anion to provide the sourceof Z component starting material, and any cation may be used ascounterion to the phosphate or similar XY₄ component. It is preferred,however, to select starting materials with counterions that give rise tovolatile by-products. Thus, it is desirable to choose ammonium salts,carbonates, oxides, hydroxides, and the like where possible. Startingmaterials with these counterions tend to form volatile by-products suchas water, ammonia, and carbon dioxide, which can be readily removed fromthe reaction mixture.

The sources of components A¹, M¹, phosphate (or other XY₄ moiety), and Zmay be reacted together in the solid state while heating for a time andtemperature sufficient to make a reaction product. The startingmaterials are provided in powder or particulate form. The powders aremixed together with any of a variety of procedures, such as by ballmilling without attrition, blending in a mortar and pestle, and thelike. Thereafter the mixture of powdered starting materials iscompressed into a tablet and/or held together with a binder material toform a closely cohering reaction mixture. The reaction mixture is heatedin an oven, generally at a temperature of about 400° C. or greater untila reaction product forms. However, when Z in the active material ishydroxide, it is preferable to heat at a lower temperature so as toavoid volatilizing water instead of incorporating hydroxyl into thereaction product.

When the starting materials contain hydroxyl for incorporation into thereaction product, the reaction temperature is preferably less than about400° C., and more preferably about 250° C. or less. One way of achievingsuch temperatures is to carry out the reaction hydrothermally. In ahydrothermal reaction, the starting materials are mixed with a smallamount of a liquid such as water, and placed in a pressurized bomb. Thereaction temperature is limited to that which can be achieved by heatingthe liquid water under pressure, and the particular reaction vesselused.

The reaction may be carried out without redox, or if desired underreducing or oxidizing conditions. When the reaction is done withoutredox, the oxidation state of the metal or mixed metals in the reactionproduct is the same as in the starting materials. Oxidizing conditionsmay be provided by running the reaction in air. Thus, oxygen from theair is used to oxidize the starting material cobalt having an averageoxidation state of +2.67 (8/3) to an oxidation state of +3 in the finalproduct.

The reaction may also be carried out with reduction. For example, thereaction may be carried out in a reducing atmosphere such as hydrogen,ammonia, methane, or a mixture of reducing gases. Alternatively, thereduction may be carried out in situ by including the reaction mixture areductant that will participate in the reaction to reduce the metal M,but that will produce by-products that will not interfere with theactive material when used later in an electrode or an electrochemicalcell. One convenient reductant to use to make the active materials ofthe invention is a reducing carbon. In a preferred embodiment, thereaction is carried out in an inert atmosphere such as argon, nitrogen,or carbon dioxide. Such reducing carbon is conveniently provided byelemental carbon, or by an organic material that can decompose under thereaction conditions to form elemental carbon or a similar carboncontaining species that has reducing power. Such organic materialsinclude, without limitation, glycerol, starch, sugars, cokes, andorganic polymers which carbonize or pyrolize under the reactionconditions to produce a reducing form of carbon. A preferred source ofreducing carbon is elemental carbon.

The stoichiometry of the reduction can be selected along with therelative stoichiometric amounts of the starting components A¹, M¹, PO₄(or other XY₄ moiety), and Z. It is usually easier to provide thereducing agent in stoichiometric excess and remove the excess, ifdesired, after the reaction. In the case of the reducing gases and theuse of reducing carbon such as elemental carbon, any excess reducingagent does not present a problem. In the former case, the gas isvolatile and is easily separated from the reaction mixture, while in thelatter, the excess carbon in the reaction product does not harm theproperties of the active material, because carbon is generally added tothe active material to form an electrode material for use in theelectrochemical cells and batteries of the invention. Conveniently also,the by-products carbon monoxide or carbon dioxide (in the case ofcarbon) or water (in the case of hydrogen) are readily removed from thereaction mixture.

The extent of reduction is not dependent simply on the amount ofhydrogen present—it is always available in excess. It is dependent onthe temperature of reaction. Higher temperatures will facilitate greaterreducing power. In addition whether one gets e.g. (PO₄)₃F or P₃O₁₁F inthe final product depend on the thermodynamics of formation of theproduct. The lower energy product will be favored.

At a temperature where only one mole of hydrogen reacts, the M⁺⁵ in thestarting material is reduced to M⁺⁴, allowing for the incorporation ofonly 2 lithiums in the reaction product. When 1.5 moles of hydrogenreact, the metal is reduced to M^(+3.5) on average, considering thestoichiometry of reduction. With 2.5 moles of hydrogen, the metal isreduced to M^(+2.5) on average. Here there is not enough lithium in thebalanced reaction to counterbalance along with the metal the −10 chargeof the (PO₄)₃F group. For this reason, the reaction product has insteada modified P₃O₁₁F moiety with a charge of −8, allowing the Li₃ tobalance the charge.

When using a reducing atmosphere, it is difficult to provide less thanan excess of reducing gas such as hydrogen. Under such as a situation,it is preferred to control the stoichiometry of the reaction by theother limiting reagents. Alternatively the reduction may be carried outin the presence of reducing carbon such as elemental carbon.Experimentally, it would be possible to use precise amounts of reductantcarbon as illustrated in the table for the case of reductant hydrogen tomake products of a chosen stoichiometry. However, it is preferred tocarry out the carbothermal reduction in a molar excess of carbon. Aswith the reducing atmosphere, this is easier to do experimentally, andit leads to a product with excess carbon dispersed into the reactionproduct, which as noted above provides a useful active electrodematerial.

The carbothermal reduction method of synthesis of mixed metal phosphateshas been described in PCT Publication WO/01/53198, Barker et al.,incorporated by reference herein. The carbothermal method may be used toreact starting materials in the presence of reducing carbon to form avariety of products. The carbon functions to reduce a metal ion in thestarting material metal M source. The reducing carbon, for example inthe form of elemental carbon powder, is mixed with the other startingmaterials and heated. For best results, the temperature should be about400° C. or greater, and up to about 950° C. Higher temperatures may beused, but are usually not required.

Generally, higher temperature (about 650° C. to about 1000° C.)reactions produce CO as a by-product whereas CO₂ production is favoredat lower temperatures (generally up to about 650° C.). The highertemperature reactions produce CO effluent and the stoichiometry requiresmore carbon be used than the case where CO₂ effluent is produced atlower temperature. This is because the reducing effect of the C to CO₂reaction is greater than the C to CO reaction. The C to CO₂ reactioninvolves an increase in carbon oxidation state of +4 (from 0 to 4) andthe C to CO reaction involves an increase in carbon oxidation state of+2 (from ground state zero to 2). In principle, such would affect theplanning of the reaction, as one would have to consider not only thestoichiometry of the reductant but also the temperature of the reaction.When an excess of carbon is used, however, such concerns do not arise.It is therefore preferred to use an excess of carbon, and control thestoichiometry of the reaction with another of the starting materials aslimiting reagent.

As noted above, the active material A¹ _(a)M¹ _(b)(XY₄)_(c)Z_(d) cancontain a mixture of alkali metals A¹, a mixture of metals M¹, a mixtureof components Z, and a phosphate group representative of the XY₄ groupin the formula. In another aspect of the invention, the phosphate groupcan be completely or partially substituted by a number of other XY₄moieties, which will also be referred to as “phosphate replacements” or“modified phosphates”. Thus, active materials are provided according tothe invention wherein the XY₄ moiety is a phosphate group that iscompletely or partially replaced by such moieties as sulfate (SO₄)²,monofluoromonophosphate, (PO₃F)²⁻, difluoromonophosphate (PO₂F)²⁻,silicate (SiO₄)⁴⁻, arsenate, antimonate, and germanate. Analogues of theabove oxygenate anions where some or all of the oxygen is replaced bysulfur are also useful in the active materials of the invention, withthe exception that the sulfate group may not be completely substitutedwith sulfur. For example thiomonophosphates may also be used as acomplete or partial replacement for phosphate in the active materials ofthe invention. Such thiomonophosphates include the anions (PO₃S)³⁻,(PO₂S₂)³⁻, (POS₃)³, and (PS₄)³⁻. They are most conveniently available asthe sodium, lithium, or potassium derivative.

To synthesize the active materials containing the modified phosphatemoieties, it is usually possible to substitute all or part of thephosphate compounds discussed above with a source of the replacementanion. The replacement is considered on a stoichiometric basis and thestarting materials providing the source of the replacement anions areprovided along with the other starting materials as discussed above.Synthesis of the active materials containing the modified phosphategroups proceeds as discussed above, either without redox or underoxidizing or reducing conditions. As was the case with the phosphatecompounds, the compound containing the modified or replacement phosphategroup or groups may also be a source of other components of the activematerials. For example, the alkali metal and/or the mixed metal M¹ maybe a part of the modified phosphate compound.

Non-limiting examples of sources of monofluoromonophosphates includeNa₂PO₃F, K₂PO₃F, (NH₄)₂PO₃F.H₂O, LiNaPO₃F.H₂O, LiKPO₃F, LiNH₄PO₃F,NaNH₄PO₃F, NaK₃(PO₃F)₂ and CaPO₃F.2H₂O. Representative examples ofsources of difluoromonophosphate compounds include, without limitation,NH₄PO₂F₂, NaPO₂F₂, KPO₂F₂, Al(PO₂F₂)₃, and Fe(PO₂F₂)₃.

When it is desired to partially or completely substitute phosphorous inthe active materials for silicon, it is possible to use a wide varietyof silicates and other silicon containing compounds. Thus, usefulsources of silicon in the active materials of the invention includeorthosilicates, pyrosilicates, cyclic silicate anions such as (Si₃O₉)⁶⁻,(Si₆O₁₈)¹²⁻ and the like and pyrocenes represented by the formula[(Si₃O₃)²⁻]_(n), for example LiAl(SiO₃)₂. Silica or SiO₂ may also beused.

Representative arsenate compounds that may be used to prepare the activematerials of the invention include H₃AsO₄ and salts of the anions[H₂AsO₄]⁻ and HAsO₄]²⁻. Sources of antimonate in the active materialscan be provided by antimony-containing materials such as Sb₂O₅,M^(I)SbO₃ where M^(I) is a metal having oxidation state +1, M^(III)SbO₄where M^(III) is a metal having an oxidation state of +3, andM^(II)Sb₂O₇ where M^(II) is a metal having an oxidation state of +2.Additional sources of antimonate include compounds such as Li₃SbO₄,NH₄H₂SbO₄, and other alkali metal and/or ammonium mixed salts of the[SbO₄]³⁻ anion.

Sources of sulfate compounds that can be used to partially or completelyreplace phosphorous in the active materials with sulfur include alkalimetal and transition metal sulfates and bisulfates as well as mixedmetal sulfates such as (NH₄)₂Fe(SO₄)₂, NH₄Fe(SO₄)₂ and the like.Finally, when it is desired to replace part or all of the phosphorous inthe active materials with germanium, a germanium containing compoundsuch as GeO₂ may be used.

To prepare the active materials containing the modified phosphategroups, it suffices to choose the stoichiometry of the startingmaterials based on the desired stoichiometry of the modified phosphategroups in the final product and react the starting materials togetheraccording to the procedures described above with respect to thephosphate materials. Naturally, partial or complete substitution of thephosphate group with any of the above modified or replacement phosphategroups will entail a recalculation of the stoichiometry of the requiredstarting materials.

In general, any anion may be combined with the alkali metal cation toprovide the alkali metal source starting material, or with a metal M¹cation to provide a metal starting material. Likewise, any cation may becombined with the halide or hydroxide anion to provide the source of Zcomponent starting material, and any cation may be used as counterion tothe phosphate or similar XY₄ component. It is preferred, however, toselect starting materials with counterions that give rise to theformation of volatile by-products during the solid state reaction. Thus,it is desirable to choose ammonium salts, carbonates, bicarbonates,oxides, hydroxides, and the like where possible. Starting materials withthese counterions tend to form volatile by-products such as water,ammonia, and carbon dioxide, which can be readily removed from thereaction mixture. Similarly, sulfur-containing anions such as sulfate,bisulfate, sulfite, bisulfite and the like tend to result in volatilesulfur oxide by-products. Nitrogen-containing anions such as nitrate andnitrite also tend to give volatile NO_(x) by-products.

As noted above, the reactions may be carried out without reduction, orin the presence of a reductant. In one aspect, the reductant, whichprovides reducing power for the reactions, may be provided in the formof a reducing carbon by including a source of elemental carbon alongwith the other particulate starting materials. In this case, thereducing power is provided by simultaneous oxidation of carbon to eithercarbon monoxide or carbon dioxide.

The starting materials containing transition metal compounds are mixedtogether with carbon, which is included in an amount sufficient toreduce the metal ion of one or more of the metal-containing startingmaterials without full reduction to an elemental metal state. (Excessquantities of the reducing carbon may be used to enhance productquality.) An excess of carbon, remaining after the reaction, functionsas a conductive constituent in the ultimate electrode formulation. Thisis an advantage since such remaining carbon is very intimately mixedwith the product active material. Accordingly, large quantities ofexcess carbon, on the order of 100% excess carbon or greater are useablein the process. In a preferred embodiment, the carbon present duringcompound formation is intimately dispersed throughout the precursor andproduct. This provides many advantages, including the enhancedconductivity of the product. In a preferred embodiment, the presence ofcarbon particles in the starting materials also provides nucleationsites for the production of the product crystals.

Alternatively or in addition, the source of reducing carbon may beprovided by an organic material. The organic material is characterizedas containing carbon and at least one other element, preferablyhydrogen. The organic material generally forms a decomposition product,referred to herein as a carbonaceous material, upon heating under theconditions of the reaction. Without being bound by theory,representative decomposition processes that can lead to the formation ofthe carbonaceous material include pyrolization, carbonization, coking,destructive distillation, and the like. These process names, as well asthe term thermal decomposition, are used interchangeably in thisapplication to refer to the process by which a decomposition productcapable of acting as a reductant is formed upon heating of a reactionmixture containing an organic material.

A typical decomposition product contains carbonaceous material. Duringreaction in a preferred embodiment, at least a portion of thecarbonaceous material formed participates as a reductant. That portionthat participates as reductant may form a volatile by-product such asdiscussed below. Any volatile by-product formed tends to escape from thereaction mixture so that it is not incorporated into the reactionproduct.

Although the invention is understood not to be limited as to themechanism of action of the organic precursor material, it believed thatthe carbonaceous material formed from decomposition of the organicmaterial provides reducing power similar to that provided by elementalcarbon discussed above. For example, the carbonaceous material mayproduce carbon monoxide or carbon dioxide, depending on the temperatureof the reaction.

In a preferred embodiment, some of the organic material providingreducing power is oxidized to a non-volatile component, such as forexample, oxygen-containing carbon materials such as alcohols, ketones,aldehydes, esters, and carboxylic acids and anhydrides. Suchnon-volatile by-products, as well as any carbonaceous material that doesnot participate as reductant (for example, any present in stoichiometricexcess or any that does not otherwise react) will tend to remain in thereaction mixture along with the other reaction products, but will not besignificantly covalently incorporated.

The carbonaceous material prepared by heating the organic precursormaterial will preferably be enriched in carbon relative to the molepercent carbon present in the organic material. The carbonaceousmaterial preferably contains from about 50 up to about 100 mole percentcarbon.

While in some embodiments the organic precursor material forms acarbonaceous decomposition product that acts as a reductant as discussedabove with respect to elemental carbon, in other embodiments a portionof the organic material may participate as reductant without firstundergoing a decomposition. The invention is not limited by the exactmechanism or mechanisms of the underlying reduction processes.

As with elemental carbon, reactions with the organic precursor materialare conveniently carried out by combining starting materials andheating. The starting materials include at least one transition metalcompound as noted above. For convenience, it is preferred to carry outthe decomposition of the organic material and the reduction of atransition metal in one step. In this embodiment, the organic materialdecomposes in the presence of the transition metal compound to form adecomposition product capable of acting as a reductant, which reactswith the transition metal compound to form a reduced transition metalcompound. In another embodiment, the organic material may be decomposedin a separate step to form a decomposition product. The decompositionproduct may then be combined with a transition metal compound to form amixture. The mixture may then be heated for a time and at a temperaturesufficient to form a reaction product comprising a reduced transitionmetal compound.

The organic precursor material may be any organic material capable ofundergoing pyrolysis or carbonization, or any other decompositionprocess that leads to a carbonaceous material rich in carbon. Suchprecursors include in general any organic material, i.e., compoundscharacterized by containing carbon and at least one other element.Although the organic material may be a perhalo compound containingessentially no carbon-hydrogen bonds, typically the organic materialscontain carbon and hydrogen. Other elements, such as halogens, oxygen,nitrogen, phosphorus, and sulfur, may be present in the organicmaterial, as long as they do not significantly interfere with thedecomposition process or otherwise prevent the reductions from beingcarried out. Precursors include organic hydrocarbons, alcohols, esters,ketones, aldehydes, carboxylic acids, sulfonates, and ethers. Preferredprecursors include the above species containing aromatic rings,especially the aromatic hydrocarbons such as tars, pitches, and otherpetroleum products or fractions. As used here, hydrocarbon refers to anorganic compound made up of carbon and hydrogen, and containing nosignificant amounts of other elements. Hydrocarbons may containimpurities having some heteroatoms. Such impurities might result, forexample, from partial oxidation of a hydrocarbon or incompleteseparation of a hydrocarbon from a reaction mixture or natural sourcesuch as petroleum.

Other organic precursor materials include sugars and othercarbohydrates, including derivatives and polymers. Examples of polymersinclude starch, cellulose, and their ether or ester derivatives. Otherderivatives include the partially reduced and partially oxidizedcarbohydrates discussed below. On heating, carbohydrates readilydecompose to form carbon and water. The term carbohydrates as used hereencompasses the D-, L-, and DL-forms, as well as mixtures, and includesmaterial from natural or synthetic sources.

In one sense as used in the invention, carbohydrates are organicmaterials that can be written with molecular formula (C)_(m) (H₂O)_(n),where m and n are integers. For simple hexose or pentose sugars, m and nare equal to each other. Examples of hexoses of formula C₆H₁₂O₆ includeallose, altose, glucose, mannose, gulose, inose, galactose, talose,sorbose, tagatose, and fructose. Pentoses of formula C₅H₁₀O₅ includeribose, arabinose, and xylose. Tetroses include erythrose and threose,while glyceric aldehyde is a triose. Other carbohydrates include thetwo-ring sugars (di-saccharides) of general formula C₁₂H₂₂O₁₁. Examplesinclude sucrose, maltose, lactose, trehalose, gentiobiose, cellobiose,and melibiose. Three-ring (trisaccharides such as raffinose) and higheroligomeric and polymer carbohydrates may also be used. Examples includestarch and cellulose. As noted above, the carbohydrates readilydecompose to carbon and water when heated to a sufficiently hightemperature. The water of decomposition tends to turn to steam under thereaction conditions and volatilize.

It will be appreciated that other materials will also tend to readilydecompose to H₂O and a material very rich in carbon. Such materials arealso intended to be included in the term “carbohydrate” as used in theinvention. Such materials include slightly reduced carbohydrates such asglycerol, sorbitol, mannitol, iditol, dulcitol, talitol, arabitol,xylitol, and adonitol, as well as “slightly oxidized” carbohydrates suchas gluconic, mannonic, glucuronic, galacturonic, mannuronic, saccharic,manosaccharic, ido-saccharic, mucic, talo-mucic, and allo-mucic acids.The formula of the slightly oxidized and the slightly reducedcarbohydrates is similar to that of the carbohydrates.

A preferred carbohydrate is sucrose. Under the reaction conditions,sucrose melts at about 150-180° C. Preferably, the liquid melt tends todistribute itself among the starting materials. At temperatures aboveabout 450° C., sucrose and other carbohydrates decompose to form carbonand water. The as-decomposed carbon powder is in the form of freshamorphous fine particles with high surface area and high reactivity.

The organic precursor material may also be an organic polymer. Organicpolymers include polyolefins such as polyethylene and polypropylene,butadiene polymers, isoprene polymers, vinyl alcohol polymers, furfurylalcohol polymers, styrene polymers including polystyrene,polystyrene-polybutadiene and the like, divinylbenzene polymers,naphthalene polymers, phenol condensation products including thoseobtained by reaction with aldehyde, polyacrylonitrile, polyvinylacetate, as well as cellulose starch and esters and ethers thereofdescribed above.

In some embodiments, the organic precursor material is a solid availablein particulate form. Particulate materials may be combined with theother particulate starting materials and reacted by heating according tothe methods described above.

In other embodiments, the organic precursor material may be a liquid. Insuch cases, the liquid precursor material is combined with the otherparticulate starting materials to form a mixture. The mixture is heated,whereupon the organic material forms a carbonaceous material in situ.The reaction proceeds with carbothermal reduction. The liquid precursormaterials may also advantageously serve or function as a binder in thestarting material mixture as noted above.

Reducing carbon is preferably used in the reactions in stoichiometricexcess. To calculate relative molar amounts of reducing carbon, it isconvenient to use an “equivalent” weight of the reducing carbon, definedas the weight per gram-mole of carbon atom. For elemental carbons suchas carbon black, graphite, and the like, the equivalent weight is about12 g/equivalent. For other organic materials, the equivalent weight pergram-mole of carbon atoms is higher. For example, hydrocarbons have anequivalent weight of about 14 g/equivalent. Examples of hydrocarbonsinclude aliphatic, alicyclic, and aromatic hydrocarbons, as well aspolymers containing predominantly or entirely carbon and hydrogen in thepolymer chain. Such polymers include polyolefins and aromatic polymersand copolymers, including polyethylenes, polypropylenes, polystyrenes,polybutadienes, and the like. Depending on the degree of unsaturation,the equivalent weight may be slightly above or below 14.

For organic materials having elements other than carbon and hydrogen,the equivalent weight for the purpose of calculating a stoichiometricquantity to be used in the reactions is generally higher than 14. Forexample, in carbohydrates it is about 30 g/equivalent. Examples ofcarbohydrates include sugars such as glucose, fructose, and sucrose, aswell as polymers such as cellulose and starch.

Although the reactions may be carried out in oxygen or air, the heatingis preferably conducted under an essentially non-oxidizing atmosphere.The atmosphere is essentially non-oxidizing so as not to interfere withthe reduction reactions taking place. An essentially non-oxidizingatmosphere can be achieved through the use of vacuum, or through the useof inert gases such as argon, nitrogen, and the like. Although oxidizinggas (such as oxygen or air), may be present, it should not be at sogreat a concentration that it interferes with the carbothermal reductionor lowers the quality of the reaction product. It is believed that anyoxidizing gas present will tend to react with the reducing carbon andlower the availability of the carbon for participation in the reaction.To some extent, such a contingency can be anticipated and accommodatedby providing an appropriate excess of reducing carbon as a startingmaterial. Nevertheless, it is generally preferred to carry out thecarbothermal reduction in an atmosphere containing as little oxidizinggas as practical.

In a preferred embodiment, reduction is carried out in a reducingatmosphere in the presence of a reductant as discussed above. The term“reducing atmosphere” as used herein means a gas or mixture of gasesthat is capable of providing reducing power for a reaction that iscarried out in the atmosphere. Reducing atmospheres preferably containone or more so-called reducing gases. Examples of reducing gases includehydrogen, carbon monoxide, methane, and ammonia, as well as mixturesthereof. Reducing atmospheres also preferably have little or nooxidizing gases such as air or oxygen. If any oxidizing gas is presentin the reducing atmosphere, it is preferably present at a level lowenough that it does not significantly interfere with any reductionprocesses taking place.

The stoichiometry of the reduction can be selected along with therelative stoichiometric amounts of the starting components A¹, M¹, PO₄(or other XY₄ moiety), and Z. It is usually easier to provide thereducing agent in stoichiometric excess and remove the excess, ifdesired, after the reaction. In the case of the reducing gases and theuse of reducing carbon such as elemental carbon or an organic material,any excess reducing agent does not present a problem. In the formercase, the gas is volatile and is easily separated from the reactionmixture, while in the latter, the excess carbon in the reaction productdoes not harm the properties of the active material, particularly inembodiments where carbon is added to the active material to form anelectrode material for use in the electrochemical cells and batteries ofthe invention. Conveniently also, the by-products carbon monoxide orcarbon dioxide (in the case of carbon) or water (in the case ofhydrogen) are readily removed from the reaction mixture.

When using a reducing atmosphere, it is difficult to provide less thanan excess of reducing gas such as hydrogen. Under such as a situation,it is preferred to control the stoichiometry of the reaction by theother limiting reagents. Alternatively the reduction may be carried outin the presence of reducing carbon such as elemental carbon.Experimentally, it would be possible to use precise amounts of reductantcarbon to make products of a chosen stoichiometry. However, it ispreferred to carry out the carbothermal reduction in a molar excess ofcarbon. As with the reducing atmosphere, this is easier to doexperimentally, and it leads to a product with excess carbon dispersedinto the reaction product, which as noted above provides a useful activeelectrode material.

Before reacting the mixture of starting materials, the particles of thestarting materials are intermingled. Preferably, the starting materialsare in particulate form, and the intermingling results in an essentiallyhomogeneous powder mixture of the precursors. In one embodiment, theprecursor powders are dry-mixed using, for example, a ball mill. Thenthe mixed powders are pressed into pellets. In another embodiment, theprecursor powders are mixed with a binder. The binder is preferablyselected so as not to inhibit reaction between particles of the powders.Preferred binders decompose or evaporate at a temperature less than thereaction temperature. Examples include mineral oils, glycerol, andpolymers that decompose or carbonize to form a carbon residue before thereaction starts, or that evaporate before the reaction starts. In oneembodiment, the binders used to hold the solid particles also functionas sources of reducing carbon, as described above. In still anotherembodiment, intermingling is accomplished by forming a wet mixture usinga volatile solvent and then the intermingled particles are pressedtogether in pellet form to provide good grain-to-grain contact.

The mixture of starting materials is heated for a time and at atemperature sufficient to form an inorganic transition metal compoundreaction product. If the starting materials include a reducing agent,the reaction product is a transition metal compound having at least onetransition metal in a lower oxidation state relative to its oxidationstate in the starting materials.

Preferably, the particulate starting materials are heated to atemperature below the melting point of the starting materials.Preferably, at least a portion of the starting material remains in thesolid state during the reaction.

The temperature should preferably be about 400° C. or greater, anddesirably about 450° C. or greater, and preferably about 500° C. orgreater, and generally will proceed at a faster rate at highertemperatures. The various reactions involve production of CO or CO₂ asan effluent gas. The equilibrium at higher temperature favors COformation. Some of the reactions are more desirably conducted attemperatures greater than about 600° C.; most desirably greater thanabout 650° C.; preferably about 700° C. or greater; more preferablyabout 750° C. or greater. Suitable ranges for many reactions are fromabout 700 to about 950° C., or from about 700 to about 800° C.

Generally, the higher temperature reactions produce CO effluent and thestoichiometry requires more carbon be used than the case where CO₂effluent is produced at lower temperature. This is because the reducingeffect of the C to CO₂ reaction is greater than the C to CO reaction.The C to CO₂ reaction involves an increase in carbon oxidation state of+4 (from 0 to 4) and the C to CO reaction involves an increase in carbonoxidation state of +2 (from ground state zero to 2). Here, highertemperature generally refers to a range of about 650° C. to about 1000°C. and lower temperature refers to up to about 650° C. Temperatureshigher than about 1200° C. are not thought to be needed.

In one embodiment, the methods of this invention utilize the reducingcapabilities of carbon in a unique and controlled manner to producedesired products having structure and alkali metal content suitable foruse as electrode active materials. The advantages are at least in partachieved by the reductant, carbon, having an oxide whose free energy offormation becomes more negative as temperature increases. Such oxide ofcarbon is more stable at high temperature than at low temperature. Thisfeature is used to produce products having one or more metal ions in areduced oxidation state relative to the precursor metal ion oxidationstate.

Referring back to the discussion of temperature, at about 700° C. boththe carbon to carbon monoxide and the carbon to carbon dioxide reactionsare occurring. At closer to about 600° C. the C to CO₂ reaction is thedominant reaction. At closer to about 800° C. the C to CO reaction isdominant. Since the reducing effect of the C to CO₂ reaction is greater,the result is that less carbon is needed per atomic unit of metal to bereduced. In the case of carbon to carbon monoxide, each atomic unit ofcarbon is oxidized from ground state zero to plus 2. Thus, for eachatomic unit of metal ion (M) which is being reduced by one oxidationstate, one half atomic unit of carbon is required. In the case of thecarbon to carbon dioxide reaction, one quarter atomic unit of carbon isstoichiometrically required for each atomic unit of metal ion (M) whichis reduced by one oxidation state, because carbon goes from ground statezero to a plus 4 oxidation state. These same relationships apply foreach such metal ion being reduced and for each unit reduction inoxidation state desired.

The starting materials may be heated at ramp rates from a fraction of adegree up to about 10° C. per minute. Higher or lower ramp rates may bechosen depending on the available equipment, desired turnaround, andother factors. It is also possible to place the starting materialsdirectly into a pre-heated oven. Once the desired reaction temperatureis attained, the reactants (starting materials) are held at the reactiontemperature for a time sufficient for reaction to occur. Typically thereaction is carried out for several hours at the final reactiontemperature. The heating is preferably conducted under non-oxidizing orinert gas such as argon or vacuum, or in the presence of a reducingatmosphere.

After reaction, the products are preferably cooled from the elevatedtemperature to ambient (room) temperature (i.e., about 10° C. to about40° C.). The rate of cooling may vary according to a number of factorsincluding those discussed above for heating rates. For example, thecooling may be conducted at a rate similar to the earlier ramp rate.Such a cooling rate has been found to be adequate to achieve the desiredstructure of the final product. It is also possible to quench theproducts to achieve a higher cooling rate, for example on the order ofabout 100° C./minute.

The general aspects of the above synthesis routes are applicable to avariety of starting materials. The metal compounds may be reduced in thepresence of a reducing agent, such as hydrogen or carbon. The sameconsiderations apply to other metal and phosphate containing startingmaterials. The thermodynamic considerations such as ease of reduction ofthe selected starting materials, the reaction kinetics, and the meltingpoint of the salts will cause adjustment in the general procedure, suchas the amount of reducing agent, the temperature of the reaction, andthe dwell time.

In a preferred embodiment, a two-step method is used to prepare thegeneral formula Li_(1+d)MPO₄F_(d) which consists of the initialpreparation of a LiMPO₄ compound (step 1), which is then reacted with xmoles of LiF to provide Li₂ MPO₄F (step 2). The starting (precursor)materials for the first step include a lithium containing compound, ametal containing compound and a phosphate containing compound. Each ofthese compounds may be individually available or may be incorporatedwithin the same compounds, such as a lithium metal compound or a metalphosphate compound.

Following the preparation in step one, step two of the reaction proceedsto react the lithium metal phosphate (provided in step 1) with a lithiumsalt, preferably lithium fluoride (LiF). The LiF is mixed in proportionwith the lithium metal phosphate to provide a lithiated transition metalfluorophosphate product. The lithiated transition metal fluorophosphatehas the capacity to provide lithium ions for electrochemical potential.

In addition to the previously described two-step method, a one stepreaction method may be used in preparing such preferred materials of thepresent invention. In one method of this invention, the startingmaterials are intimately mixed and then reacted together when initiatedby heat. In general, the mixed powders are pressed into a pellet. Thepellet is then heated to an elevated temperature. This reaction can berun under an air atmosphere or a non-oxidizing atmosphere. In anothermethod, the lithium metal phosphate compound used as a precursor for thelithiated transition metal fluorophosphate reaction can be formed eitherby a carbothermal reaction, or by a hydrogen reduction reaction.

The general aspects of the above synthesis route are applicable to avariety of starting materials. The metal compounds may be reduced in thepresence of a reducing agent, such as hydrogen or carbon. The sameconsiderations apply to other metal and phosphate containing startingmaterials. The thermodynamic considerations such as ease of reduction ofthe selected starting materials, the reaction kinetics, and the meltingpoint of the salts will cause adjustment in the general procedure, suchas the amount of reducing agent, the temperature of the reaction, andthe dwell time.

The first step of a preferred two-step method includes reacting alithium containing compound (lithium carbonate, Li₂CO₃), a metalcontaining compound having a phosphate group (for example, nickelphosphate, Ni₃(PO₄)₂.xH₂O, which usually has more than one mole ofwater), and a phosphoric acid derivative (such as a diammonium hydrogenphosphate, DAHP). The powders are pre-mixed with a mortar and pestleuntil uniformly dispersed, although various methods of mixing may beused. The mixed powders of the starting materials are pressed intopellets. The first stage reaction is conducted by heating the pellets inan oven at a preferred heating rate to an elevated temperature, and heldat such elevated temperature for several hours. A preferred ramp rate ofabout 2° C./minute is used to heat to a preferable temperature of about800° C. Although in many instances a heating rate is desirable for areaction, it is not always necessary for the success of the reaction.The reaction is carried out under a flowing air atmosphere (e.g., when Mis Ni or Co), although the reaction could be carried out in an inertatmosphere such as N₂ or Ar (when M is Fe). The flow rate will depend onthe size of the oven and the quantity needed to maintain the atmosphere.The reaction mixture is held at the elevated temperature for a timesufficient for the reaction product to be formed. The pellets are thenallowed to cool to ambient temperature. The rate at which a sample iscooled may vary.

In the second step, the Li₂ MPO₄F active material is prepared byreacting the LiMPO₄ precursor made in step one with a lithium salt,preferably lithium fluoride LiF. Alternatively, the precursors mayinclude a lithium salt other than a halide (for example, lithiumcarbonate) and a halide material other than lithium fluoride (forexample ammonium fluoride). The precursors for step 2 are initiallypre-mixed using a mortar and pestle until uniformly dispersed. Themixture is then pelletized, for example by using a manual pellet pressand an approximate 1.5″ diameter die-set. The resulting pellet ispreferably about 5 mm thick and uniform. The pellets are thentransferred to a temperature-controlled tube furnace and heated at apreferred ramp rate of about 2° C./minute to an ultimate temperature ofabout 800° C. The entire reaction is conducted in a flowing argon gasatmosphere. Prior to being removed from the box oven, the pellet isallowed to cool to room temperature. As stated previously, the rate inwhich the pellet is cooled does not seem to have a direct impact on theproduct.

An alternate embodiment of the present invention is the preparation of amixed metal-lithium fluorophosphate compound. The two stage reactionresults in the general nominal formula Li₂M′_(1-m)M″_(m)PO₄F wherein0≦m<1. In general, a lithium or other alkali metal compound, at leasttwo metal compounds, and a phosphate compound are reacted together in afirst step to provide a lithium mixed metal phosphate precursor. Aspreviously described in other reactions, the powders are mixed togetherand pelletized. The pellet is then transferred to atemperature-controlled tube furnace equipped with a flowing inert gas(such as argon). The sample is then heated for example at a ramp rate ofabout 2° C./minute to an ultimate temperature of about 750° C. andmaintained at this temperature for eight hours or until a reactionproduct is formed. As can be seen in various examples, the specifictemperatures used vary depending on what initial compounds were used toform the precursor, but the standards described in no way limit theapplication of the present invention to various compounds. Inparticular, a high temperature is desirable due to the carbothermalreaction occurring during the formation of the precursor. Following theheating of the pellet for a specified period of time, the pellet wascooled to room temperature.

The second stage provides the reaction of the lithium mixed metalphosphate compound with an alkali metal halide such as lithium fluoride.Following the making of the pellet from the lithium mixed metalphosphate precursor and the lithium fluoride, the pellet is placedinside a covered and sealed nickel crucible and transferred to a boxoven. In general, the nickel crucible is a convenient enclosure for thepellet although other suitable containers, such as a ceramic crucible,may also be used. The sample is then heated rapidly to an ultimatetemperature of about 700° C. and maintained at this temperature forabout 15 minutes. The crucible is then removed from the box oven andcooled to room temperature. The result is a lithiated transition metalfluorophosphate compound of the present invention.

In addition to the general nominal formula Li₂M′_(1-m)M″_(m)PO₄F, anon-stoichiometric mixed metal lithium fluorophosphate having thegeneral nominal formula Li_(1+d)M′_(1-m)M″_(m)PO₄F_(d) is furtherprovided. The same conditions are met when preparing thenon-stoichiometric formula as are followed when preparing thestoichiometric formula. In the non-stoichiometric mixed metal lithiumfluorophosphate, the mole ratio of lithiated transition metal phosphateprecursor to lithium fluoride is about 1.0 to 0.25. The precursorcompounds are pre-mixed using a mortar and pestle and then pelletized.The pellet is then placed inside a covered and sealed crucible andtransferred to a box oven. The sample is rapidly heated to an ultimatetemperature of about 700° C. and maintained at this temperature forabout 15 minutes. Similar conditions apply when preparing the nominalgeneral formula Li_(1+d)MPO₄F_(d).

Referring back to the discussion of the lithium fluoride and metalphosphate reaction, the temperature of reaction is preferably about 400°C. or higher but below the melting point of the metal phosphate, andmore preferably at about 700° C. It is preferred to heat the precursorsat a ramp rate in a range from a fraction of a degree to about 10° C.per minute and preferably about 2° C. per minute. Once the desiredtemperature is attained, the reactions are held at the reactiontemperature from about 10 minutes to several hours, depending on thereaction temperature chosen. The heating may be conducted under an airatmosphere, or if desired may be conducted under a non-oxidizing orinert atmosphere. After reaction, the products are cooled from theelevated temperature to ambient (room) temperature (i.e. from about 10°C. to about 40° C.). Desirably, the cooling occurs at a rate of about50° C./minute. Such cooling has been found to be adequate to achieve thedesired structure of the final product in some cases. It is alsopossible to quench the products at a cooling rate on the order of about100° C./minute. In some instances, such rapid cooling may be preferred.A generalized rate of cooling has not been found applicable for certaincases, therefore the suggested cooling requirements vary.

Method of Manufacturing A′_(e)M′_(f)O_(g):

The alkali metal transition metal oxide, denoted by the formulaA′_(e)M′_(f)O_(g), is prepared by reacting an alkali metal (A′)containing compound and a transition metal (M′) containing compound. Thesources of A′ and M′ may be reacted together in a solid state whileheating for a time and temperature sufficient to make a reactionproduct. The starting material are provided in powder or particulateform. The powders are mixed together with any of a variety ofprocedures, such as by ball milling without attrition, blending in amortar and pestle, and the like. Thereafter the mixture of powderedstarting materials is compressed into a tablet and/or held together witha binder material to form a closely cohering reaction mixture. Thereaction mixture is heated in an oven, generally at a temperature ofabout 400° C. or greater until a reaction product forms.

Method of Manufacturing Modified Manganese Oxide (A³ _(h)Mn_(i)O₄):

The modified A³ _(h)Mn_(i)O₄ compound is prepared by reacting cubicspinel manganese oxide particles and particles of a alkali metalcompound in air for a time and at a temperature sufficient to decomposeat least a portion of the compound, providing a treated lithiummanganese oxide. The reaction product is characterized as particleshaving a core or bulk structure of cubic spinel lithium manganese oxideand a surface region which is enriched in Mn⁺⁴ relative to the bulk.X-ray diffraction data and x-ray photoelectron spectroscopy data areconsistent with the structure of the stabilized LMO being a central bulkof cubic spinel lithium manganese oxide with a surface layer or regioncomprising A₂MnO₃, where A is an alkali metal.

For a treated lithium manganese oxide, a method of preparing comprisesfirst forming a mixture of the lithium manganese oxide (LMO) particlesand an alkali metal compound. Next, the mixture is heated for a time andat a temperature sufficient to decompose at least a portion of thealkali metal compound in the presence of a lithium manganese oxide.

The mixture may be formed in a number of ways. Preferred methods ofmixing result in very well-mixed starting materials. For example, in oneembodiment, powders of the LMO and the alkali metal compound are milledtogether without attrition. In another, the powders can be mixed with amortar and pestle. In another embodiment, the LMO powder may be combinedwith a solution of the alkali metal compound prior to heating.

The mixture preferably contains less than 50% by weight of the alkalimetal compound, preferably less than about 20%. The mixture contains atleast about 0.1% by weight of the alkali metal compound, and preferably1% by weight or more. In a preferred embodiment, the mixture containsfrom about 0.1% to about 20%, preferably from about 0.1% to about 10%,and more preferably from about 0.4% to about 6% by weight of the alkalimetal compound.

The alkali metal compound is a compound of lithium, sodium, potassium,rubidium or cesium. The alkali metal compound serves as a source ofalkali metal ion in particulate form. Preferred alkali metal compoundsare sodium compounds and lithium compounds. Examples of compoundsinclude, without limitation, carbonates, metal oxides, hydroxides,sulfates, aluminates, phosphates and silicates. Examples of lithiumcompounds thus include, without limitation, lithium carbonates, lithiummetal oxides, lithium mixed metal oxides, lithium hydroxides, lithiumaluminates, and lithium silicates, while analogous sodium compounds arealso preferred. A preferred lithium compound is lithium carbonate, whichdecomposes in the presence of LMO at a temperature in a range of 600° C.to 750° C. Likewise, sodium carbonate and sodium hydroxide are preferredsodium compounds. Depending on the temperature selected, a portion ofthe alkali metal compound is decomposed or reacted with the lithiummanganese oxide and a portion of the alkali metal compound is dispersedon the surface of the lithium manganese oxide particles. The result is atreated spinel lithium manganese oxide characterized by reduced surfacearea and increased alkali metal content as compared to an untreatedspinel lithium manganese oxide. In one alternative, essentially all of alithium or sodium compound is decomposed or reacted with the lithiummanganese oxide.

In one aspect, the heating is conducted in an air atmosphere or in aflowing air atmosphere. In one embodiment, the heating is conducted inat least two stages beginning at an elevated temperature, followed bycooling to an ambient temperature. In one example, three progressivestages of heating are conducted. As an example, a first stage is in arange of about 650 to 700° C., a second stage is at a lower temperatureon the order of 600° C., and a third stage is at a lower temperature ina range of about 400 to 500° C., followed by permitting the product tocool to an ambient condition. Quenching is considered optional. Theheating is conducted for a time up to about 10 hours.

In another non-limiting example, two stages of heating may be used, forexample by first heating in a first furnace at a temperature of about600-750° C. for about 30 minutes, then removing the material to a secondfurnace set a about 450° C. for about one hour, ensuring that the secondfurnace has a good supply of flowing air, and finally removing thematerial from the second furnace to allow it to cool. Single stageheating may also be used. For example, the mixture may be heated in asingle box furnace set at about 650° C. for about 30 minutes.Thereafter, the furnace may be turned off and the material allowed tocool in the furnace while ensuring there is a good supply of flowing airthroughout.

In another alternative, the heating and cooling may be conducted in aMultiple Heat Zone Rotary Furnace. Here, the material is fed into thehottest part of the furnace, typically at 650-750° C. Then, the materialtravels through the furnace to another heat zone at a lower temperature,for example, 600° C. Then the material progress to a zone at 400° C. to450° C., and finally is allowed to cool to room temperature. A goodsupply of flowing air is provided throughout the furnace.

The product of the aforesaid method is a composition comprisingparticles of spinel lithium manganese oxide (LMO) enriched with alkalimetal by a decomposition product of the alkali metal compound forming apart of each of the LMO particles. The product is preferablycharacterized by having a reduced surface area and improved capacityretention with cycling, expressed in milliamp hours per gram as comparedto the initial, non-modified spinel. In one aspect, the decompositionproduct is a reaction product of the LMO particles and the alkali metalcompound. For the case where the alkali metal is lithium, a lithium-richspinel is prepared that can be represented by the formulaLi_(1+x)Mn_(2-x)O₄ where x is greater than zero and less than or equalto about 0.20. Preferably x is greater than or equal to about 0.081.This lithium-rich spinel product is preferably prepared from a startingmaterial of the formula Li_(1+x)Mn_(2-x)O₄ where 0≦x≦0.08, andpreferably the starting material has x greater than 0.05. Thelithium-rich spinel product has an Li content greater than that of theLMO starting material.

The product of the aforesaid method will depend upon the extent ofheating during heat treatment. If all the alkali metal compound isdecomposed or reacted, then the alkali metal enriched spinel isproduced. If some of the alkali metal compound (for example, lithiumcarbonate or sodium carbonate) remains unreacted or not decomposed, thenit is dispersed on and adhered to the surface of the alkali metalenriched spinel particles.

Once each of the active materials are formed, proportions are combinedin a powder mixture. Each active material is physically combinedtogether to form a homogenous mixtures containing relative proportion ofactive materials.

Electrodes:

The present invention also provides electrodes comprising an electrodeactive material blend of the present invention. In a preferredembodiment, the electrodes of the present invention comprise anelectrode active material mixture of this invention, a binder; and anelectrically conductive carbonaceous material.

In a preferred embodiment, the electrodes of this invention comprise:

-   -   (a) from about 25% to about 95%, more preferably from about 50%        to about 90%, active material blend;    -   (b) from about 2% to about 95% electrically conductive material        (e.g., carbon black); and    -   (c) from about 3% to about 20% binder chosen to hold all        particulate materials in contact with one another without        degrading ionic conductivity.        (Unless stated otherwise, all percentages herein are by weight.)        Cathodes of this invention preferably comprise from about 50% to        about 90% of active material, about 5% to about 30% of the        electrically conductive material, and the balance comprising        binder. Anodes of this invention preferably comprise from about        50% to about 95% by weight of the electrically conductive        material (e.g., a preferred graphite), with the balance        comprising binder.

Electrically conductive materials among those useful herein includecarbon black, graphite, powdered nickel, metal particles, conductivepolymers (e.g., characterized by a conjugated network of double bondslike polypyrrole and polyacetylene), and mixtures thereof. Bindersuseful herein preferably comprise a polymeric material and extractableplasticizer suitable for forming a bound porous composite. Preferredbinders include halogenated hydrocarbon polymers (such aspoly(vinylidene chloride) and poly((dichloro-1,4-phenylene)ethylene),fluorinated urethanes, fluorinated epoxides, fluorinated acrylics,copolymers of halogenated hydrocarbon polymers, epoxides, ethylenepropylene diamine termonomer (EPDM), ethylene propylene diaminetermonomer (EPDM), polyvinylidene difluoride (PVDF), hexafluoropropylene(HFP), ethylene acrylic acid copolymer (EAA), ethylene vinyl acetatecopolymer (EVA), EAA/EVA copolymers, PVDF/HFP copolymers, and mixturesthereof.

In a preferred process for making an electrode, the electrode activematerial is mixed into a slurry with a polymeric binder compound, asolvent, a plasticizer, and optionally the electroconductive material.The active material slurry is appropriately agitated, and then thinlyapplied to a substrate via a doctor blade. The substrate can be aremovable substrate or a functional substrate, such as a currentcollector (for example, a metallic grid or mesh layer) attached to oneside of the electrode film. In one embodiment, heat or radiation isapplied to evaporate the solvent from the electrode film, leaving asolid residue. The electrode film is further consolidated, where heatand pressure are applied to the film to sinter and calendar it. Inanother embodiment, the film may be air-dried at moderate temperature toyield self-supporting films of copolymer composition. If the substrateis of a removable type it is removed from the electrode film, andfurther laminated to a current collector. With either type of substrateit may be necessary to extract the remaining plasticizer prior toincorporation into the battery cell.

Batteries:

The batteries of the present invention comprise:

(a) a first electrode comprising an active material of the presentinvention;

(b) a second electrode which is a counter-electrode to said firstelectrode; and

(c) an electrolyte between said electrodes.

The electrode active material of this invention may comprise the anode,the cathode, or both. Preferably, the electrode active materialcomprises the cathode.

The active material of the second, counter-electrode is any materialcompatible with the electrode active material of this invention. Inembodiments where the electrode active material comprises the cathode,the anode may comprise any of a variety of compatible anodic materialswell known in the art, including lithium, lithium alloys, such as alloysof lithium with aluminum, mercury, manganese, iron, zinc, andintercalation based anodes such as those employing carbon, tungstenoxides, and mixtures thereof. In a preferred embodiment, the anodecomprises:

-   -   (a) from about 0% to about 95%, preferably from about 25% to        about 95%, more preferably from about 50% to about 90%, of an        insertion material;    -   (b) from about 2% to about 95% electrically conductive material        (e.g., carbon black); and    -   (c) from about 3% to about 20% binder chosen to hold all        particulate materials in contact with one another without        degrading ionic conductivity.        In a particularly preferred embodiment, the anode comprises from        about 50% to about 90% of an insertion material selected from        the group active material from the group consisting of metal        oxides (particularly transition metal oxides), metal        chalcogenides, and mixtures thereof. In another preferred        embodiment, the anode does not contain an insertion active, but        the electrically conductive material comprises an insertion        matrix comprising carbon, graphite, cokes, mesocarbons and        mixtures thereof. One preferred anode intercalation material is        carbon, such as coke or graphite, which is capable of forming        the compound Li_(X)C. Insertion anodes among those useful herein        are described in U.S. Pat. No. 5,700,298, Shi et al., issued        Dec. 23, 1997; U.S. Pat. No. 5,712,059, Barker et al., issued        Jan. 27, 1998; U.S. Pat. No. 5,830,602, Barker et al., issued        Nov. 3, 1998; and U.S. Pat. No. 6,103,419, Saidi et al., issued        Aug. 15, 2000; all of which are incorporated by reference        herein.

In embodiments where the electrode active material comprises the anode,the cathode preferably comprises:

-   -   (a) from about 25% to about 95%, more preferably from about 50%        to about 90%, active material;    -   (b) from about 2% to about 95% electrically conductive material        (e.g., carbon black); and    -   (c) from about 3% to about 20% binder chosen to hold all        particulate materials in contact with one another without        degrading ionic conductivity.        Active materials useful in such cathodes include electrode        active materials of this invention, as well as metal oxides        (particularly transition metal oxides), metal chalcogenides, and        mixtures thereof. Other active materials include lithiated        transition metal oxides such as LiCoO₂, LiNiO₂, and mixed        transition metal oxides such as LiCo_(1-m)Ni_(m)O₂, where 0<m<1.        Another preferred active material includes lithiated spinel        active materials exemplified by compositions having a structure        of LiMn₂O₄, as well as surface treated spinels such as disclosed        in U.S. Pat. No. 6,183,718, Barker et al., issued Feb. 6, 2001,        incorporated by reference herein. Blends of two or more of any        of the above active materials may also be used. The cathode may        alternatively further comprise a basic compound to protect        against electrode degradation as described in U.S. Pat. No.        5,869,207, issued Feb. 9, 1999, incorporated by reference        herein.

In one embodiment, batteries are provided wherein one of the electrodescontains an active material and optionally mixed with a basic compoundas described above, wherein the battery further contains somewhere inthe system a basic compound that serves to neutralize the acid generatedby decomposition of the electrolyte or other components. Thus, a basiccompound such as but not limited to those discussed above, may be addedto the electrolyte to form a battery having increased resistance tobreakdown over multiple charge/recharge cycles.

The batteries of this invention also comprise a suitable electrolytethat provides a physical separation but allows transfer of ions betweenthe cathode and anode. The electrolyte is preferably a material thatexhibits high ionic conductivity, as well as having insular propertiesto prevent self-discharging during storage. The electrolyte can beeither a liquid or a solid. A liquid electrolyte comprises a solvent andan alkali metal salt that together form an ionically conducting liquid.So called “solid electrolytes” contain in addition a matrix materialthat is used to separate the electrodes.

One preferred embodiment is a solid polymeric electrolyte, made up of asolid polymeric matrix and a salt homogeneously dispersed via a solventin the matrix. Suitable solid polymeric matrices include those wellknown in the art and include solid matrices formed from organicpolymers, inorganic polymers or a solid matrix-forming monomer and frompartial polymers of a solid matrix forming monomer.

In another variation, the polymer, solvent and salt together form a gelwhich maintains the electrodes spaced apart and provides the ionicconductivity between electrodes. In still another variation, theseparation between electrodes is provided by a glass fiber mat or othermatrix material and the solvent and salt penetrate voids in the matrix.

Preferably, the salt of the electrolyte is a lithium or sodium salt.Such salts among those useful herein include LiAsF₆, LiPF₆, LiClO₄,LiB(C₆H₅)₄, LiAlCl₄, LiBr, LiBF₄, LiSO₃CF₃, LiN(SO₂CF₃)₂, LiN(SO₂C₂F₅)₂,and mixtures thereof, as well as sodium analogs, with the less toxicsalts being preferable. The salt content is preferably from about 5% toabout 65%, preferably from about 8% to about 35% (by weight ofelectrolyte). A preferred salt is LiBF₄. In a preferred embodiment, theLiBF₄ is present at a molar concentration of from 0.5M to 3M, preferably1.0M to 2.0M, and most preferably about 1.5M.

Electrolyte compositions among those useful herein are described in U.S.Pat. No. 5,418,091, Gozdz et al., issued May 23, 1995; U.S. Pat. No.5,508,130, Golovin, issued Apr. 16, 1996; U.S. Pat. No. 5,541,020,Golovin et al., issued Jul. 30, 1996; U.S. Pat. No. 5,620,810, Golovinet al., issued Apr. 15, 1997; U.S. Pat. No. 5,643,695, Barker et al.,issued Jul. 1, 1997; U.S. Pat. No. 5,712,059, Barker et al., issued Jan.27, 1998; U.S. Pat. No. 5,851,504, Barker et al., issued Dec. 22, 1998;U.S. Pat. No. 6,020,087, Gao, issued Feb. 1, 2000; U.S. Pat. No.6,103,419, Saidi et al., issued Aug. 15, 2000; and PCT Application WO01/24305, Barker et al., published Apr. 5, 2001; all of which areincorporated by reference herein.

The solvent is preferably a low molecular weight organic solvent addedto the electrolyte, which may serve the purpose of solvating theinorganic ion salt. The solvent is preferably a compatible, relativelynon-volatile, aprotic, polar solvent. Examples of solvents among thoseuseful herein include chain carbonates such as dimethyl carbonate (DMC),diethyl carbonate (DEC), dipropylcarbonate (DPC), and ethyl methylcarbonate (EMC); cyclic carbonates such as ethylene carbonate (EC),propylene carbonate (PC) and butylene carbonate; ethers such as diglyme,triglyme, and tetraglyme; lactones; esters, dimethylsulfoxide,dioxolane, sulfolane, and mixtures thereof. Examples of pairs of solventinclude EC/DMC, EC/DEC, EC/DPC and EC/EMC.

In a preferred embodiment, the electrolyte solvent contains a blend oftwo components. The first component contains one or more carbonatesselected from the group consisting of alkylene carbonates (cycliccarbonates), having a preferred ring size of from 5 to 8, C₁-C₆ alkylcarbonates, and mixtures thereof. The carbon atoms of the alkylenecarbonates may be optionally substituted with alkyl groups, such asC₁-C₆ carbon chains. The carbon atoms of the alkyl carbonates may beoptionally substituted with C₁-C₄ alkyl groups. Examples ofunsubstituted cyclic carbonates are ethylene carbonate (5-memberedring), 1,3-propylene carbonate (6-membered ring), 1,4-butylene carbonate(7-membered ring), and 1,5-pentylene carbonate (8-membered ring).Optionally the rings may be substituted with lower alkyl groups,preferably methyl, ethyl, propyl, or isopropyl groups. Such structuresare well known; examples include a methyl substituted 5-membered ring(also known as 1,2-propylene carbonate, or simply propylene carbonate(PC)), and a dimethyl substituted 5-membered ring carbonate (also knownas 2,3-butylene carbonate) and an ethyl substituted 5-membered ring(also known as 1,2-butylene carbonate or simply butylene carbonate (BC).Other examples include a wide range of methylated, ethylated, andpropylated 5-8 membered ring carbonates. Preferred alkyl carbonatesinclude diethyl carbonate, methyl ethyl carbonate, dimethyl carbonateand mixtures thereof. DMC is a particularly preferred alkyl carbonate.In a preferred embodiment, the first component is a 5- or 6-memberedalkylene carbonate. More preferably, the alkylene carbonate has a5-membered ring. In a particularly preferred embodiment, the firstcomponent comprises ethylene carbonate.

The second component in a preferred embodiment is selected from thegroup of cyclic esters, also known as lactones. Preferred cyclic estersinclude those with ring sizes of 4 to 7. The carbon atoms in the ringmay be optionally substituted with alkyl groups, such as C₁-C₆ chains.Examples of unsubstituted cyclic esters include the 4-memberedβ-propiolactone (or simply propiolactone); γ-butyrolactone (5-memberedring), δ-valerolactone (6-membered ring) and ε-caprolactone (7-memberedring). Any of the positions of the cyclic esters may be optionallysubstituted, preferably by methyl, ethyl, propyl, or isopropyl groups.Thus, preferred second components include one or more solvents selectedfrom the group of unsubstituted, methylated, ethylated, or propylatedlactones selected from the group consisting of propiolacone,butyrolactone, valerolactone, and caprolactone. (It will be appreciatedthat some of the alkylated derivatives of one lactone may be named as adifferent alkylated derivative of a different core lactone. Toillustrate, γ-butyrolactone methylated on the γ-carbon may be named asγ-valerolactone.)

In a preferred embodiment, the cyclic ester of the second component hasa 5- or a 6-membered ring. Thus, preferred second component solventsinclude one or more compounds selected from γ-butyrolactone(gamma-butyrolactone), and δ-valerolactone, as well as methylated,ethylated, and propylated derivatives. Preferably, the cyclic ester hasa 5-membered ring. In a particular preferred embodiment, the secondcomponent cyclic ester comprises γ-butyrolactone.

The preferred two component solvent system contains the two componentsin a weight ratio of from about 1:20 to a ratio of about 20:1. Morepreferably, the ratios range from about 1:10 to about 10:1 and morepreferably from about 1:5 to about 5:1. In a preferred embodiment thecyclic ester is present in a higher amount than the carbonate.Preferably, at least about 60% (by weight) of the two component systemis made up of the cyclic ester, and preferably about 70% or more. In aparticularly preferred embodiment, the ratio of cyclic ester tocarbonate is about 3 to 1. In one embodiment, the solvent system is madeup essentially of γ-butyrolactone and ethylene carbonate. A preferredsolvent system thus contains about 3 parts by weight γ-butyrolactone andabout 1 part by weight ethylene carbonate. The preferred salt andsolvent are used together in a preferred mixture comprising about 1.5molar LiBF₄ in a solvent comprising about 3 parts γ-butyrolactone andabout 1 part ethylene carbonate by weight.

A separator allows the migration of ions while still providing aphysical separation of the electric charge between the electrodes, toprevent short-circuiting. The polymeric matrix itself may function as aseparator, providing the physical isolation needed between the anode andcathode. Alternatively, the electrolyte can contain a second oradditional polymeric material to further function as a separator. In apreferred embodiment, the separator prevents damage from elevatedtemperatures within the battery that can occur due to uncontrolledreactions preferably by degrading upon high temperatures to provideinfinite resistance to prevent further uncontrolled reactions.

The separator membrane element is generally polymeric and prepared froma composition comprising a copolymer. A preferred composition contains acopolymer of about 75% to about 92% vinylidene fluoride with about 8% toabout 25% hexafluoropropylene copolymer (available commercially fromAtochem North America as Kynar FLEX) and an organic solvent plasticizer.Such a copolymer composition is also preferred for the preparation ofthe electrode membrane elements, since subsequent laminate interfacecompatibility is ensured. The plasticizing solvent may be one of thevarious organic compounds commonly used as solvents for electrolytesalts, e.g., propylene carbonate or ethylene carbonate, as well asmixtures of these compounds. Higher-boiling plasticizer compounds suchas dibutyl phthalate, dimethyl phthalate, diethyl phthalate, and trisbutoxyethyl phosphate are preferred. Inorganic filler adjuncts, such asfumed alumina or silanized fumed silica, may be used to enhance thephysical strength and melt viscosity of a separator membrane and, insome compositions, to increase the subsequent level of electrolytesolution absorption. In a non-limiting example, a preferred electrolyteseparator contains about two parts polymer per one part of fumed silica.

A preferred battery comprises a laminated cell structure, comprising ananode layer, a cathode layer, and electrolyte/separator between theanode and cathode layers. The anode and cathode layers comprise acurrent collector. A preferred current collector is a copper collectorfoil, preferably in the form of an open mesh grid. The current collectoris connected to an external current collector tab, for a description oftabs and collectors. Such structures are disclosed in, for example, U.S.Pat. No. 4,925,752, Fauteux et al, issued May 15, 1990; U.S. Pat. No.5,011,501, Shackle et al., issued Apr. 30, 1991; and U.S. Pat. No.5,326,653, Chang, issued Jul. 5, 1994; all of which are incorporated byreference herein. In a battery embodiment comprising multipleelectrochemical cells, the anode tabs are preferably welded together andconnected to a nickel lead. The cathode tabs are similarly welded andconnected to a welded lead, whereby each lead forms the polarized accesspoints for the external load.

Lamination of assembled cell structures is accomplished by conventionalmeans by pressing between metal plates at a temperature of about120-160° C. Subsequent to lamination, the battery cell material may bestored either with the retained plasticizer or as a dry sheet afterextraction of the plasticizer with a selective low-boiling pointsolvent. The plasticizer extraction solvent is not critical, andmethanol or ether are often used.

In a preferred embodiment, a electrode membrane comprising the electrodeactive material (e.g., an insertion material such as carbon or graphiteor a insertion compound) dispersed in a polymeric binder matrix. Theelectrolyte/separator film membrane is preferably a plasticizedcopolymer, comprising a polymeric separator and a suitable electrolytefor ion transport. The electrolyte/separator is positioned upon theelectrode element and is covered with a positive electrode membranecomprising a composition of a finely divided lithium insertion compoundin a polymeric binder matrix. An aluminum collector foil or gridcompletes the assembly. A protective bagging material covers the celland prevents infiltration of air and moisture.

In another embodiment, a multi-cell battery configuration may beprepared with copper current collector, a negative electrode, anelectrolyte/separator, a positive electrode, and an aluminum currentcollector. Tabs of the current collector elements form respectiveterminals for the battery structure.

In a preferred embodiment of a lithium-ion battery, a current collectorlayer of aluminum foil or grid is overlaid with a positive electrodefilm, or membrane, separately prepared as a coated layer of a dispersionof insertion electrode composition. This is preferably an insertioncompound such as the active material of the present invention in powderform in a copolymer matrix solution, which is dried to form the positiveelectrode. An electrolyte/separator membrane is formed as a driedcoating of a composition comprising a solution containing VdF:HFPcopolymer and a plasticizer solvent is then overlaid on the positiveelectrode film. A negative electrode membrane formed as a dried coatingof a powdered carbon or other negative electrode material dispersion ina VdF:HFP copolymer matrix solution is similarly overlaid on theseparator membrane layer. A copper current collector foil or grid islaid upon the negative electrode layer to complete the cell assembly.Therefore, the VdF:HFP copolymer composition is used as a binder in allof the major cell components, positive electrode film, negativeelectrode film, and electrolyte/separator membrane. The assembledcomponents are then heated under pressure to achieve heat-fusion bondingbetween the plasticized copolymer matrix electrode and electrolytecomponents, and to the collector grids, to thereby form an effectivelaminate of cell elements. This produces an essentially unitary andflexible battery cell structure.

Cells comprising electrodes, electrolytes and other materials amongthose useful herein are described in the following documents, all ofwhich are incorporated by reference herein: U.S. Pat. No. 4,668,595,Yoshino et al., issued May 26, 1987; U.S. Pat. No. 4,792,504, Schwab etal., issued Dec. 20, 1988; U.S. Pat. No. 4,830,939, Lee et al., issuedMay 16, 1989; U.S. Pat. No. 4,935,317, Fauteaux et al., issued Jun. 19,1990; U.S. Pat. No. 4,990,413, Lee et al., issued Feb. 5, 1991; U.S.Pat. No. 5,037,712, Shackle et al., issued Aug. 6, 1991; U.S. Pat. No.5,262,253, Golovin, issued Nov. 16, 1993; U.S. Pat. No. 5,300,373,Shackle, issued Apr. 5, 1994; U.S. Pat. No. 5,399,447, Chaloner-Gill, etal., issued Mar. 21, 1995; U.S. Pat. No. 5,411,820, Chaloner-Gill,issued May 2, 1995; U.S. Pat. No. 5,435,054, Tonder et al., issued Jul.25, 1995; U.S. Pat. No. 5,463,179, Chaloner-Gill et al., issued Oct. 31,1995; U.S. Pat. No. 5,482,795, Chaloner-Gill., issued Jan. 9, 1996; U.S.Pat. No. 5,660,948, Barker, issued Aug. 26, 1997; and U.S. Pat. No.6,306,215, Larkin, issued Oct. 23, 2001. A preferred electrolyte matrixcomprises organic polymers, including VdF:HFP. Examples of casting,lamination and formation of cells using VdF:HFP are as described in U.S.Pat. Nos. 5,418,091, Gozdz et al., issued May 23, 1995; U.S. Pat. No.5,460,904, Gozdz et al., issued Oct. 24, 1995; U.S. Pat. No. 5,456,000,Gozdz et al., issued Oct. 10, 1995; and U.S. Pat. No. 5,540,741, Gozdzet al., issued Jul. 30, 1996; all of which are incorporated by referenceherein.

The electrochemical cell architecture is typically governed by theelectrolyte phase. A liquid electrolyte battery generally has acylindrical shape, with a thick protective cover to prevent leakage ofthe internal liquid. Liquid electrolyte batteries tend to be bulkierrelative to solid electrolyte batteries due to the liquid phase andextensive sealed cover. A solid electrolyte battery, is capable ofminiaturization, and can be shaped into a thin film. This capabilityallows for a much greater flexibility when shaping the battery andconfiguring the receiving apparatus. The solid state polymer electrolytecells can form flat sheets or prismatic (rectangular) packages, whichcan be modified to fit into the existing void spaces remaining inelectronic devices during the design phase.

The description of the invention is merely exemplary in nature and,thus, variations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

The following are examples of the present invention but in no way limitthe scope of the present invention.

Example 1

A blend of the present invention comprising LiFe_(0.9)Mg_(0.1)PO₄ andLiCoO₂ is made as follows. Each of the active materials are madeindividually and then combined to form a blend of active materialparticles for use in an electrode.

(a) The first active material LiFe_(0.9)Mg_(0.1)PO⁴ is made as follows.The following sources containing Li, Fe, Mg, and phosphate are providedcontaining the respective elements in a molar ratio of 1.0:0.9:0.1:1.0.

0.50 moles Li₂CO₃ (mol. wt. 73.88 g/mol), 1.0 mol Li 36.95 g 0.45 molFe₂O₃ (159.7 g/mol), 0.9 mol Fe 71.86 g 0.10 moles Mg(OH)₂ (58 g/mol),0.1 mol Mg 5.83 g 1.00 moles (NH₄)₂HPO₄ (132 g/mol), 1.0 mol phosphate132.06 g 0.45 moles elemental carbon (12 g/mol) (=100% mass excess) 5.40g

The above starting materials are combined and ball milled to mix theparticles. Thereafter, the particle mixture is pelletized. Thepelletized mixture is heated for 4-20 hours at 750° C. in an oven in anargon atmosphere. The sample is removed from the oven and cooled. Anx-ray diffraction pattern shows that the material has an olivine typecrystal structure.

(b) The second active material LiCoO₂ is made as follows or can beobtained commercially. The following sources containing Li, Co, andoxygen are provided containing the respective elements in a molar ratioof 1.0:1.0:2.0.

0.50 moles Li₂CO₃ (mol. wt. 73.88 g/mol), 1.0 mol Li 36.95 g 1.0 molesCoCo3 (118.9 g/mol), 1.0 mol Co 118.9 g

The above starting materials are combined and ball milled to mix theparticles. Thereafter, the particle mixture is pelletized. Thepelletized mixture is calcined for 4-20 hours, most preferably 5-10 at900° C. in an oven. The sample is removed from the oven and cooled.

(c) The first active material LiFe_(0.9)Mg_(0.1)PO₄ and second activematerial LiCoO₂ are physically combined in a 67.5/32.5 weight percentmixtures respectively.

An electrode is made with 80% of the active material, 10% of Super Pconductive carbon, and 10% poly vinylidene difluoride. A cell with thatelectrode as cathode and a carbon intercalation anode is constructedwith an electrolyte comprising 1M LiBF₄ dissolved in a 3:1 mixture byweight of γ-butyrolactone:ethylene carbonate.

In the foregoing Example,LiCu_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(39.75)F_(0.025) can besubstituted for LiFe_(0.9)Mg_(0.1)PO₄ with substantially equivalentresults.

Example 2

A blend of the present invention comprisingLiCu_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025) andLiFe_(0.95)Mg_(0.05)PO₄ is made as follows. Each of the active materialsare made individually and then combined to form a blend of activematerial particles for use in an electrode.

(a) The first active materialLiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025) is made asfollows. The following sources containing Li, Co, Fe, Al, Mg, phosphate,and fluoride are provided containing the respective elements in a molarratio of 1.0:0.8:0.1:0.025:0.05:1.0:0.025.

0.05 moles Li₂CO₃ (mol. wt. 73.88 g/mol), 0.1 mol Li 3.7 g 0.02667 molesCo₃ O₄ (240.8 g/mol), 0.08 mol Co 6.42 g 0.005 moles Fe₂ O₃ (159.7g/mol), 0.01 mol Fe 0.8 g 0.0025 moles Al (OH)₃ (78 g/mol), 0.0025 molAl 0.195 g 0.005 moles Mg(OH)₂ (58 g/mol), 0.005 mol Mg 0.29 g 0.1 moles(NH₄)₂HPO₄ (132 g/mol), 0.1 mol phosphate 13.2 g 0.00125 moles NH₄ HF₂(57 g/mol), 0.0025 mol F 0.071 g 0.2 moles elemental carbon (12 g/mol)(=100% mass excess) 2.4 g

The above starting materials are combined and ball milled to mix theparticles. Thereafter, the particle mixture is pelletized. Thepelletized mixture is heated for 4-20 hours at 750° C. in an oven in anargon atmosphere. The sample is removed from the oven and cooled. Anx-ray diffraction pattern shows that the material has an olivine typecrystal structure.

(b) The second active material LiFe_(0.95)Mg_(0.95)PO₄ is made asfollows. The following sources containing Li, Fe, Mg, and phosphate areprovided containing the respective elements in a molar ratio of1.0:0.95:0.05:1.0.

0.50 moles Li₂CO₃ (mol. wt. 73.88 g/mol), 1.0 mol Li 36.95 g 0.475 molFe₂O₃ (159.7 g/mol), 0.95 mol Fe 75.85 g 0.05 moles Mg(OH)₂ (58 g/mol),0.05 mol Mg 2.915 g 1.00 moles (NH₄)₂HPO₄ (132 g/mol), 1.0 mol phosphate132.06 g 0.45 moles elemental carbon (12 g/mol) (=100% mass excess) 5.40g

The above starting materials are combined and ball milled to mix theparticles. Thereafter, the particle mixture is pelletized. Thepelletized mixture is heated for 4-20 hours at 750° C. in an oven in anargon atmosphere. The sample is removed from the oven and cooled. Anx-ray diffraction pattern shows that the material has an olivine typecrystal structure.

(c) The first active materialLiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025) and secondactive material LiFe_(0.95)Mg_(0.05)PO₄ are physically combined in a50/50 weight percent mixtures respectively.

An electrode is made with 80% of the active material, 10% of Super Pconductive carbon, and 10% poly vinylidene difluoride. A cell with thatelectrode as cathode and a carbon intercalation anode is constructedwith an electrolyte comprising 1M LiBF4 dissolved in a 3:1 mixture byweight of γ-butyrolactone:ethylene carbonate.

Example 3

A blend of the present invention comprising LiFe_(0.95)Mg_(0.05)PO₄ andLiNi_(0.75)Co_(0.25)O₂ is made as follows. Each of the active materialsare made individually and then combined to form a blend of activematerial particles for use in an electrode.

(a) The first active material LiFe_(0.95)Mg_(0.05)PO₄ is made asfollows. The following sources containing Li, Fe, Mg, and phosphate areprovided containing the respective elements in a molar ratio of1.0:0.95:0.05:1.0.

0.50 moles Li₂CO₃ (mol. wt. 73.88 g/mol), 1.0 mol Li 36.95 g 0.95 molFePO₄ ((150.82 g/mol), 0.95 mol Fe 143.28 g 0.05 moles Mg(OH)₂ (58g/mol), 0.1 mol Mg 2.915 g 0.05 moles (NH₄)₂HPO₄ (132 g/mol), 0.05 molphosphate 0.33 g 0.45 moles elemental carbon (12 g/mol) (=100% massexcess) 5.40 g

The above starting materials are combined and ball milled to mix theparticles. Thereafter, the particle mixture is pelletized. Thepelletized mixture is heated for 4-20 hours at 750° C. in an oven in anargon atmosphere. The sample is removed from the oven and cooled. Anx-ray diffraction pattern shows that the material has an olivine typecrystal structure.

(b) The second active material LiNi_(0.75)Co_(0.25)O₂ is made as followsor can be commercially obtained. The following sources containing Li,Ni, Co, and oxygen are provided containing the respective elements in amolar ratio of 1.0:0.75:0.25:2.0.

0.50 moles Li₂CO₃ (73.88 g/mol), 1.0 mol Li 36.95 g 0.75 moles Ni(OH)₂(92.71 g/mol), 0.75 mol Ni 69.53 g 0.25 moles CoCO₃ (118.9 g/mol), 0.25mol Co 29.73 g

The above starting materials are combined and ball milled to mix theparticles. Thereafter, the particle mixture is pelletized. Thepelletized mixture is calcined for 4-20 hours, most preferably 5-10 at900° C. in an oven. The sample is removed from the oven and cooled.

(c) The first active material LiFe_(0.95)Mg_(0.05)PO₄ and second activematerial LiNi_(0.75)Co_(0.25)O₂ are physically combined in a 67.5/32.5weight percent mixtures respectively.

An electrode is made with 80% of the active material, 10% of Super Pconductive carbon, and 10% poly vinylidene difluoride. A cell with thatelectrode as cathode and a carbon intercalation anode is constructedwith an electrolyte comprising 1M LiBF₄ dissolved in a 3:1 mixture byweight of γ-butyrolactone:ethylene carbonate.

Example 4

A blend of the present invention comprising LiFe_(0.95)Mg_(0.05)PO₄ andγ-LiV₂O₅ is made as follows. Each of the active materials are madeindividually and then combined to form a blend of active materialparticles for use in an electrode.

(a) The first active material LiFe_(0.95)Mg_(0.05)PO₄ is made asfollows. The following sources containing Li, Fe, Mg, and phosphate areprovided containing the respective elements in a molar ratio of1.0:0.95:0.05:1.0.

0.50 moles Li₂CO₃ (mol. wt. 73.88 g/mol), 1.0 mol Li 36.95 g 0.95 molFePO₄ (150.82 g/mol), 0.95 mol Fe 143.28 g 0.05 moles Mg(OH)₂ (58g/mol), 0.1 mol Mg 2.915 g 0.05 moles (NH₄)₂HPO₄ (132 g/mol), 0.05 molphosphate 0.33 g 0.45 moles elemental carbon (12 g/mol) (=100% massexcess) 5.40 g

The above starting materials are combined and ball milled to mix theparticles. Thereafter, the particle mixture is pelletized. Thepelletized mixture is heated for 4-20 hours at 750° C. in an oven in anargon atmosphere. The sample is removed from the oven and cooled. Anx-ray diffraction pattern shows that the material has an olivine typecrystal structure.

(b) The second active material γ-LiV2O5 is made as follows. Thefollowing sources containing Li, V, and oxygen are provided containingthe respective elements in a molar ratio of 1.0:2.0:5.0.

1.0 moles V₂O₅ (181.88 g/mol), 1.0 mol 181.88 g 0.5 moles Li₂CO₃ (92.71g/mol), 0.5 mol Li 36.95 g 0.25 moles carbon (12 g/mol) (=25% massexcess) 3.75 g

The above starting materials are combined and ball milled to mix theparticles. Thereafter, the particle mixture is pelletized. Thepelletized mixture is heated in an inert atmosphere (i.e. argon) for 1-2hours, most preferably around one hour at between 400-650° C., morepreferably 600° C. in an oven. The sample is removed from the oven andcooled.

(c) The first active material LiFe_(0.95)Mg_(0.05)PO₄ and second activematerial γ-LiV₂O₅ are physically combined in a 67.5/32.5 weight percentmixtures respectively.

An electrode is made with 80% of the active material, 10% of Super Pconductive carbon, and 10% poly vinylidene difluoride. A cell with thatelectrode as cathode and a carbon intercalation anode is constructedwith an electrolyte comprising 1M LiBF₄ dissolved in a 3:1 mixture byweight of γ-butyrolactone:ethylene carbonate.

Example 5

A blend of the present invention comprising LiFe_(0.95)Mg_(0.05)PO₄ andLi₂CuO₂ is made as follows. Each of the active materials are madeindividually and then combined to form a blend of active materialparticles for use in an electrode.

(a) The first active material LiFe_(0.95)Mg_(0.05)PO₄ is made asfollows. The following sources containing Li, Fe, Mg, and phosphate areprovided containing the respective elements in a molar ratio of1.0:0.95:0.05:1.0.

1.0 moles LiH₂PO₄ (103.93 g/mol), 1.0 mol Li 36.95 g 0.475 mol Fe₂O₃(159.7 g/mol), 0.95 mol Fe 75.85 g 0.05 moles Mg(OH)₂ (58 g/mol), 0.1mol Mg 2.915 g 0.45 moles elemental carbon (12 g/mol) (=100% massexcess) 5.40 g

The above starting materials are combined and ball milled to mix theparticles. Thereafter, the particle mixture is pelletized. Thepelletized mixture is heated for 4-20 hours at 750° C. in an oven in anargon atmosphere. The sample is removed from the oven and cooled. Anx-ray diffraction pattern shows that the material has an olivine typecrystal structure.

(b) The second active material Li₂CuO₂ is made as follows. The followingsources containing Li, Cu, and oxygen are provided containing therespective elements in a molar ratio of 2.0:1.0:2.0.

2.0 moles LiOH (23.948 g/mol), 2.0 mol Li 47.896 g 1.0 moles CuO (79.545g/mol), 1.0 mol Cu 79.545 g

Prior to the mixing of the copper oxide with the lithium hydroxide, thelithium hydroxide salt is predried to about 120° C. for about 24 hours.The lithium salt is thoroughly ground, so that the particle size isapproximately equivalent to the particle size of the copper oxide. Thelithium hydroxide and copper oxide are mixed. Thereafter, the particlemixture is pelletized. The pelletized mixture is heated in an aluminacrucible in an inert atmosphere at a rate of approximately 2° C./minuteup to about 455° C. and is held at such temperature for approximately 12hours. The temperature is ramped again at the same rate to achieve atemperature of 825° C. and then held at such temperature forapproximately 24 hours. The sample is then cooled, and followed by arepeat heating for approximately 6 hours at 455° C., 6 hours at 650° C.,and 825° C. for 12 hours.

(c) The first active material LiFe_(0.95)Mg_(0.05)PO₄ and second activematerial Li₂CuO₂ are physically combined in a 67.5/32.5 weight percentmixtures respectively.

An electrode is made with 80% of the active material, 10% of Super Pconductive carbon, and 10% poly vinylidene difluoride. A cell with thatelectrode as cathode and a carbon intercalation anode is constructedwith an electrolyte comprising 1M LiB F₄ dissolved in a 3:1 mixture byweight of γ-butyrolactone:ethylene carbonate.

In the foregoing Example,LiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025) can besubstituted for LiFe_(0.95)Mg_(0.05)PO₄ with substantially equivalentresults.

1. An electrode active material comprising two or more groups ofparticles having differing chemical compositions, wherein each group ofparticles comprises a material selected from: (a) materials of theformula A² _(e)M² _(f)O_(g); and (b) materials of the formula A³_(h)Mn_(i)O₄; wherein (i) A², and A³ are independently selected from thegroup consisting of Li, Na, K, and mixtures thereof, 0<e≦6; h≦2.0; andi≦2; (ii) M² is one or more metals, comprising at least one metalselected from the group consisting of Fe, Co, Ni, Mo, V, Zr, Ti, Mo, andCr, and 1≦f≦6; (iii) 0<g≦15; (iv) M², e, f, g, h, and i, are selected soas to maintain electroneutrality of said compound; and (v) said materialof the formula A³ _(h)Mn_(i)O₄ has an inner and an outer region, whereinthe inner region comprises a cubic spinel manganese oxide, and the outerregion comprises a manganese oxide that is enriched in Mn⁺⁴ relative tothe inner region.
 2. An electrode active material according to claim 1,comprising a material of the formula A² _(e)M² _(f)O_(g).
 3. Anelectrode active material according to claim 2, wherein A² comprises Li.4. An electrode active material according to claim 3, wherein M² is M⁴_(k)M⁵ _(m)M⁶ _(n), wherein M⁴ is a transition metal selected from thegroup consisting of Fe, Co, Ni, Mo, V, Zr, Ti, Cr, and mixtures thereof;M⁵ is one or more transition metal from Groups 4 to 11 of the PeriodicTable; M⁶ is at least one metal selected from Group 2, 12, 13, or 14 ofthe Periodic Table; and k+m+n=f.
 5. An electrode active materialaccording to claim 4, wherein M⁶ is selected from the group consistingof Mg, Ca, Al, and mixtures thereof, and n>0.
 6. An electrode activematerial according to claim 4, comprising a material of the formulaLiNi_(r)Co_(s)M⁶ _(t)O₂, wherein 0<(r+s)≦1, and 0≦t<1.
 7. An electrodeactive material according to claim 1, comprising a material selectedfrom the group consisting of LiNiO₂, LiCoO₂, γ-LiV₂O₅ and mixturesthereof.
 8. An electrode active material comprising a first group ofparticles comprising an active material selected from the groupconsisting of LiFe_(0.9)Mg_(0.1)PO₄ and LiFe_(0.8)Mg_(0.2)PO₄, andmixtures thereof and a second group of particles comprising an activematerial selected from the group consisting of γ-LiV₂O₅,LiNi_(0.8)Co_(0.15)Al_(0.05)O₂, LiCoO₂, LiNi_(r)Co_(s)O₂,Li_(1+p)Mn_(2-p)O₄, LiNiO₂, Li₂CuO₂ and mixtures thereof, wherein0<(r+s)≦1, and 0≦p<0.2.
 9. An electrode active material comprising afirst group of particles comprising an active material selected from thegroup consisting of LiFe_(0.9)Mg_(0.1)PO₄ and LiFe_(0.8)Mg_(0.2)PO₄, andmixtures thereof and a second group of particles comprising an activematerial having an inner and an outer region, wherein the inner regioncomprises a cubic spinel manganese oxide, and the outer region comprisesa manganese oxide that is enriched in Mn⁺⁴ relative to the inner region.10. An electrode active material comprising a first group of particlescomprising an active material selected from the group consisting ofLiFe_(0.9)Mg_(0.1)PO₄, LiFe_(0.8)Mg_(0.2)PO₄, LiFe_(0.95)Mg_(0.05)PO₄,LiCo_(0.9)Mg_(0.1)PO₄ and mixtures thereof; and a second group ofparticles comprising an active material selected from the groupconsisting of LiCoO₂, LiNi_(r)Co_(s)O₂, Li_(1+p)Mn_(2-p)O₄, Li₂CuO₂, andmixtures thereof, wherein 0<(r+s)≦1, and 0≦p<0.2.
 11. A lithium batterycomprising: (a) a first electrode comprising a powder mixture accordingto claim 1, (b) a second electrode which is a counter-electrode to saidfirst electrode; and (c) an electrolyte between said electrodes.